How to create a Game’s Store

When creating a game, the in-game store or shop is one of the most critical parts of it. It is the part that has the tendency to be the least fun for the user but is the most crucial for the developer. Without a shop, most in-app purchases won’t happen in your game. This is why, even though it may not be fun, a developer should pay close attention when building up his shop. For our upcoming game, Tumble Panda, we put some effort and time into our shop and went through some iterations. With this game as an example, I want to show you how you can build a nice store.

 Step 1: Identify your store’s criteria

First, you might want to identify critical criteria for your game’s store. As for us, we worked out the following points. Now, as I’m a lover of simplicity and like having one screen doing one thing, I like to also have a more minimalistic design, for example with rather big instead of many buttons. Of course, this criteria may vary from individual preferences and from game to game: Our biggest point was that it should be easy and seamless to use. This is a very soft formulation, so soft, that it is probably a criteria for every app ever specified. This is why, from this starting point, we worked out six other, more specific points:

  1. The design should fit the rest of the game.
  2. The design should be as minimalistic as possible while still highlighting the different functionalities of the virtual goods.
  3. Animations should be as quiet as possible.
  4. There should be little  enough goods to not confuse the user while still providing enough variety to make purchases attractive.
  5. The flow from overview to purchase should be done with as little clicks as possible.
  6. There should be possibilities to gain in-game currency without having to pay “real” money.

Furthermore, in order to keep it easy for us, and since we would need to experiment a bit to create a balanced variety of goods, we wanted to have the content easy to configure.

Step 2: Implement

Once the soft and hard criteria for your game are done, you should start implementing according to them. You will probably go through some iterations in which you will experiment, test and refine your shop more and more. Usually there area many ideas in the beginning, so it is probably the easiest to simply start implementing analog by sketching your shop and its transitions first. Here is how this looked in our case:

The first sketch of Tumble panda's store

The first sketch of Tumble panda’s store

From the number of screens, your store will probably look somewhat similar. A screen to purchase items and a screen for purchasing your in-game currency with “real” money are the vital parts of it. Then it is time to test and try out.

First, we thought about a simplistic design that would show all the items we offer represented by icons. Once the user clicked on one of these items, he would be taken to the next step of the shopping procedure in which he would see the item’s details, like description and price, a bigger image of the item and confirm and cancel buttons.

Steps 3, 4 and 5: Iterate

When testing this approach, we found that the initial display of small  icons for all the items and details to them on click was simple, but only on the first view. Because for the user to find out about the different items, he would need to click on each, read through the description and then click on the next item. We had a trade-off between a simplistic design and a simplistic user interaction path.

The first implementation of our store

The first implementation of our store, with one icon for each element

This was the reason why we decided to go with a design that displays more information, which can be positive but also negative. We decided to put our items in two categories which can be accessed by tabs. For the item’s representation, we chose lists:

Our store with tabs and a list

Our store with tabs and a list

This changes are the reason why it is important for you to chose a method in which you can quickly test rough concepts and ideas, like just sketching them first, then implementing a basic version and putting the final finish only in the end. This way, major changes will be less pricy when they appear on  this stage. Imagine you implement your complete store and then realize you sticked to the wrong concept and need to implement the whole UI interaction again.

You need to as well talk to your users and have your different ideas tested. Then implement changes, based on your user’s feedback. In our case, the testing team consists of a mixture of employees, friends and relatives which span from the age of 7 to 52. This test-team should be not too big and fast in making responses so that you can really have a process of showing your work, receiving immediate feedback, improving upon this feedback, and showing your work again.

Once you decided on the basic way your store’s design and interaction  works, it’s time to go over the smaller parts. It should be a set of iterations with continuous improvements, followed by tests, followed by the next iteration.

Here is an overview over the various iterations we took on our store. As you can see, we sometimes only did small graphical changes, trying to improve more and more. Then, in the end, we gave it the final touch and it is now in the state in which it will go into the beta testing phase.


The iterations of Tumble Panda's shop

The iterations of Tumble Panda’s shop

Step 6: Balance your content

When you look closely to the changes we made, you may notice that not only the graphics changed, but also the content of the store. In the process of development we found out, that some of the items we thought would be good to have in our store weren’t but others were.

The items in a store should be useful and affordable enough to make some of them easy to purchase, but not cheap enough to buy through the game without making real money purchases. The prices of your store and your virtual currency determine the value you give to the user’s time. If you for example give up to 50 gold coins for a level for which the user needs 2 minutes to play and offer 1000 gold for $0.99, that would give the users time a value of $0.02475 per minute. Obviously this value shouldn’t be too high nor insultingly low.

Furthermore, the items in your store should provide some use to the user. In our case, we created two categories for Tumble Panda, items that are consumable and which can be used once and need to be re-purchased, and items that improve the protagonist’s power gradually and stay forever.

To balance your content well, I recommend to do some more iterations with your Alpha-testers, track their behavior, for example with Flurry (we use this one) or Google Analytics, and ask them for more feedback.


In the end I hope we met all the criteria we specified. Some things may still need adjustment, but the beta phase will show.

Besides a clear set of criteria to measure against, consecutive iterations with a set of testers involved are crucial to creating the store that not only you but also your users love. Personally, I also like to break the content down to the essential elements with every screen being responsible for exactly one thing, while keeping buttons and touch areas big, since the store is designed for a mobile device. The store of Temple Run for example really appeals to me, since it has all the stuff in one place, while items are still clearly grouped using separators and the user does not need many clicks to purchase an item.

I’m interested in unconventional and great ways of implementing stores and monetization systems. If you know any, please feel invited to share in the comments.

P.S.: We are looking for beta testers for Tumble panda. If you want to join, please let me know.


Creating an Awesome Game Menu – the Process

Today I want to talk about one of the games we have currently in progress. The game’s name is Tumble Panda, it’s a physics based casual game and so far, we have never shown it to the public.

In this post will cover the process of creating the menu. We are not done yet, some assets are still placeholder. But I think you will get the Idea of the concept, both in terms of design and user experience.

Fortunately we are in the lucky position of having a lot of great people supporting us at Andlabs. That’s especially true when it comes to graphics design. For Tumble Panda, our lead graphical hero, Fabian, and his friend, the illustration-master Darren, are helping us.

0 Prerequisites

The general guideline for the game are:

  • It should be kids friendly
  • It should copy existing patterns as little as possible
  • The user experience should be as smooth as possible

Especially the last point seems to be mutually exclusive with most of the existing monetization strategies for mobile games, but that will be part of another post. Back to the menu.

1 Setting

One of the first steps we took was to decide on the overall setting the game should be in. Since Darren is a great fan of comic books and the main character was set to be a Panda, we decided to have a combination of a comic and an asian style.

Comic style

Comic style

Asian style

Asian style

2 First, rough, attempt

Fabian suggested doing the menu in a style that’s really close to a comic. The whole menu should look like the grid of tiles a comic usually is drawn in. I couldn’t really imagine what he was talking about, so he quickly created a quick and dirty first draft of the main menu:

First menu draft

First draft of the menu

This draft very clearly shows the basic structure. The different entry points to the submenus are comic tiles. The importance of the different submenus is shown by the tile’s size.

3 Navigation

Next was the navigation. Since comics don’t consist of five boxes only, we decided to have all menus in one, with the main menu in the center. Whenever a tile in the main menu – the entry point to a submenu – is clicked, the camera moves to the corresponding part of the screen – just as the eye would when reading a comic:

Draft of the menu and submenus

Draft of the menu and submenus

As you can see we already balanced the importance of the different submenus a bit by changing the sizes of the tiles in the main menu.

On the top left stays a promo graphic. On the top right is the most important part of the screen, the tile that leads the user to right, to the menu in which he can select the level he wants to play. On the bottom left is the least important, the ‘about’-button, which leads to a submenu on the left. In the center is the ‘highscores’-button (which will soon change into ‘achievements’), that leads down and on the bottom right is the button that is most important for us, the button which leads the user to the store. Controversially this button navigates to the top instead of the right, as one would expect.

4 Animations

We decided to implement animations that don’t make a lot of visual noise in the menus. The movement from one menu to another is simply done with a move animation with a cubic ease in and out.

Take a look at the main menu, which now is very close to its final design:

Main menu

Main menu

Please notice that the final design of the main character is not yet decided, which is, why you can see three different types of Panda illustrations in the above screenshot.

The clouds that are visible in the background of the store-tile are constantly moving. This kind of moving clouds can also be found on each of the submenus. Furthermore the Panda in the play-tile is moving (‘tumbling’) from side to side.

When looking at the store:

Menu store

Menu store

You will notice the two placeholder-graphics on the left side, saying “goodies” and “upgrades”. This areas work as tabs. The transition between the “goodies” and the “upgrades” content in the list on the right side is done by an animation that moves the complete list out of  and then back into the screen, with changed content. The same animation is used when switching between different worlds in the play-submenu.

That’s almost all we have on animations in the menus. A bit more is to come when I will write about our store.

5 The big picture

Here’s the current state of the menus in  overview form:

Overview over current state of the menus

Overview over the current state of the menus

While it is obvious that some of the graphics will still be exchanged, you probably get a good picture of where we want to go with this game. Since it runs in immersive mode when possible, every screen also has its own software back button.

6 Too little moving images!

Here’s the tl,dr-part. Since talking about animations and graphics doesn’t give me the best idea of the way something will finally look, I assume there are some people among you that feel about it the same way. That’s why I made a short video:


In the next posts I will talk in a bit more detail about the thoughts we had on the individual submenus of the game.

In the meantime, while I think the menu we’ve created is pretty awesome, I’m really curious for your feedback. This is Tumble Panda’s first public appearance on the internet and I’m very curious about the impression it gives you – so please give me the honor of sharing your honest opinion with me.

Simplified Logging in Android

Logging is one of the important tools for debugging an application.

When logging in Android, one usually writes code like

public class LoggingSample {

    public static final String TAG = "LoggingSample";

    public void loggingMethod() {   

    final String formattedTestString = "first argument = %s, " + 
             "second argument = %s";
    final String firstArgument = "abc";
    final Object secondArgument = new  Object() {
        public String toString() {
            return "123";
    Log.d(TAG, "loggingMethod(): " + 
           String.format(formattedTestString, firstArgument,


This then results in an output like

D/ LoggingSample: loggingMethod(): first argument = abc, second argument = 123

We need to add a tag and many times, in order to reproduce procedures, the name of the calling method. Not much of a deal, but since logging is done frequently it is often repeated

Since we don’t like repetitions, we decided to make it a little easier. Instead of the above, we now type

    L.d(formattedTestString, firstArgument, secondArgument);

To get an output like

D/LoggingSample:26(18510): onCreate(): first argument = abc, second argument = 123

What we get is the calling class’s name and the line number as a tag, the calling methods name plus the formatted string as a message.


If you are interested in this type of logging, you can now git clone the ANDLABS Android Utils and add them as a library project.


What do you think? How do you use logging? Please share your thoughts in the comments.

Getting started with the Universal Tween Engine

This is a guest post by Alexander Fröhlich. Alexander is a freelance developer and is supporting ANDLABS at its libgdx-based development. 

If you are not familiar with libgdx yet, please check out the first part of this series, the Getting started with libgdx-guide.


1 Tweening?

“Tweening” in games is the process of creating intermediate states and thus frames between two or more given states.

Example (Sprite Translation):
The most simple example would be moving a sprite or image from one x1, y1 position to another x2, y2 position on the screen.

Yet, as you might already suspect, this “Universal Tween Engine” is capable of manipulating not only x, y coordinates for sprite objects…. no, this cross-platform-engine written entirely in java language lets you tween every property of any object given that it has its getter/setter methods attached.

In this tutorial I will show you how this comes in handy for game developers when building ingame hints or tutorials for their game.

The following sample code illustrates basic use and setup of the universal tween engine in a libgdx code project.

2 Ingame Tutorial Tweening

First of all, declare your tweenManager instance. The tweenManager lets you keep track and manage all your tweens (i.e. tweening, tween actions and so on)

public class MyGame implements ApplicationListener {

    // Only one manager is needed, like a 
    // libgdx Spritebatch (

    private static TweenManager tweenManager;


Instantiate the manager inside create() of your libgdx lifecycle:

Register an accessor class, which is the key binding between the manager and the object to be tweened. Here this will be the TutorMessage class. (see below).
So after calling registerAccessor every single object of class TutorMessage we create can be tweened by the TweenManager.

public void create() {
    setTweenManager(new TweenManager());
    Tween.setCombinedAttributesLimit(4);// default is 3, yet
                                        // for rgba color setting          
                                        //we need to raise to 4! 
    Tween.registerAccessor(TutorMessage.class, new 


The TutorMessage’s are the internal game objects for this sample which hold the position, scale and color message attributes.

public class TutorMessage {

    private String message; // string objects can not be tweened
    private float x;
    private float y;
    private Color color;
    private float scale;


To tween these message properties and make them accessible by the manager we have to declare how getting and setting every single attribute works.

So we define 3 sections (POS_XY, SCALE, COLOR) that process the current float[] values, handled over by the manager during runtime when tweening is active.

Of course same applies for the setters.

public class TutorMessageAccessor implements TweenAccessor<TutorMessage> {

    public static final int POS_XY = 1;
    public static final int SCALE = 2
    public static final int COLOR = 3;

    public int getValues(TutorMessage target, int tweenType, 
                           float[] returnValues) {
        switch (tweenType) {
            case POS_XY:
                returnValues[0] = target.getX();
                returnValues[1] = target.getY();
                return 2;

            case SCALE:
                returnValues[0] = target.getScale();
                return 1;

            case COLOR:
                returnValues[0] = target.getColor().r;
                returnValues[1] = target.getColor().g;
                returnValues[2] = target.getColor().b;
                returnValues[3] = target.getColor().a;
                return 4;

                assert false; 
                return -1;

    public void setValues(TutorMessage target, int tweenType, 
                            float[] newValues) {
        switch (tweenType) {
            case POS_XY: 
                target.setPosition(newValues[0], newValues[1]); 

            case SCALE: 

            case COLOR:
                Color c = target.getColor();
                c.set(newValues[0], newValues[1], newValues[2], 

                assert false;

Having bind our TutorMessage class to the TweenManager we can now integrate it into the game.
Remember? We want to provide a kind of ingame tutorial system. So every time our user should see an animated on-screen help, we call the now defined method. The tweenHelpingHand method takes the parameter targetX, targetY that indicate the position where the helping hand (sprite) and its bound message (bitmapfont) should move to.

Then we say Tween
  .to (
      – TutorMessage currentTm ( the message to be moved )
      – int TutorMessageAccessor.POS_XY (constant to select which property should be tweened)
      – float 3f (total tweening duration)
  .target (
    – targetX, targetY ( the final screen position of our tweened message )
  .ease (
    – TweenEquations.easeOutCirc ( one possible interpolation pattern – i.e. moving pattern here)
  .start (
    – MyGame.getTweenManager()  ( binds this tween to the manager )

private void tweenHelpingHand(int targetX, int targetY) {

    // kill current tween - or pre-existing

    // move, TutorMessageAccessor.POS_XY, 3f)
         .target(targetX, targetY)

    // colorize, TutorMessageAccessor.COLOR, 3f)
         .target(1f, 1f, 1f, 1f)


Finally we have to call update inside the libgdx render() method to have the started Tween be updated constantly.


Here you go!
Enjoy this very powerful any easy to use tweening library.

Combining Scene2d animations and Tweening is also possible. You just have to write the ActorAccessor binding class and provide access (getter/setter) to its properties.
Like with Scene2d actions, the universal tween engine also allows sequencing of multiple tweens!


If you have any questions or suggestions, please leave a comment.

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