Although I had originally created this blog mainly to be a home base for my mobile game Play The Field, after some consideration I’ve decided to put a heavier emphasis on mobile game design in general. I think this will be more interesting for readers, as well as myself, in the long run.
In this post I’m going to focus on input control differences between desktop and mobile games, and how that effects gameplay.
For the desktop, the primary devices for input are the time-honored combination of mouse and keyboard. On mobile devices, a touch screen is the primary method. For now I’ll stay away from alternate methods such as console-style controllers, acceleration sensors, audio, and other custom devices like food pedals.
The first thing to note is that, given the user does not have any major physical handicaps, you can manage inputing nearly any type of content on either desktop or mobile. What is different, and what really matters, is how easy it is for each content type.
To give a specific example, typing up a document can be done on either a standard desktop keyboard, or on a in-screen mobile keyboard, but the latter is typically much difficult or at minimum awkward due to lack of force feedback, key sizes, and other factors. This isn’t the best comparison, however, since you can get a mobile keyboard to partially solve this problem.
For the rest of this post I’d like to focus on comparison of the desktop mouse vs the mobile touch screen, as they tend to be the main input methods used for a majority of games on each platform.
On the surface, these two input methods seem quite similar – after all, in both cases the user can pick a point roughly corresponding to the display screen. In other words if I want to click on a balloon which is floating on the screen, the conceptual action of clicking vs touching it is not that different.
One of the differences is that mice have two or three buttons, while a touch screen effectively has one. Also, mouse double clicks don’t translate too well to double taps on the screen; they can be done in theory but are rarely used in the mobile apps I’ve used.
What I consider even more important is the fact that tapping all over a mobile screen is just a lot more physical work than moving a mouse cursor the same relative distance on a desktop monitor. The higher the mouse sensitivity is set the less distance the hand has to move to translate to larger distance on the monitor. At the highest setting, crossing the entire monitor can take less than an inch of real distance, whereas on a mobile device the user has to cross the physical size of the entire device.
Another weak point of mobile devices’ touch screens is accuracy. Since you usually don’t know the exact pixel you are clicking on (like with a mouse cursor), there is uncertainty about exactly where you are clicking. The smaller the screen the larger this uncertainty is relative to the screen’s total size. Much of the problem here stems from the fact that the place you are touching is exactly the place that you can’t see, since your finger is obscuring your vision there. One pretty effective technique used in iOS to combat the accuracy problem when selecting text is to show a magnified view of the text and selected area. Buttons and the like are also typically much larger on mobile apps.
What all these drawbacks mean is that input for mobile games, and mobile apps in general, tends to be much simpler. If you look at the most popular apps, you’ll find a good percentage of them have, well what I feel as maddeningly simple input control systems.
To give one iOS example that is a bit dated, the game Jetpack Joyride involves a character in what looks at first like a classic side-scroller, except the major difference is the control is super simple. Tap to jump, don’t tap to do nothing. The character moves to the right automatically so no other buttons required.
Another more example, a bit more modern, is Hellrider, where a motorcyclist runs literally through “hell”. The controls are equally simple: tap to change directions, don’t tap to keep driving in the same direction. The only two directions are forward-left and forward-right.
Both of these games were actually kind of fun for the first few minutes, but with so many years of mouse+keyboard experience I just couldn’t get over how limited and simplistic the input controls where. Sure, mobile games with such simplistic controls (and believe me, they are a dime a dozen) can have great elements like a great graphics, engaging music, challenges, and require a certain level of strategy and persistence to beat, the extreme lack of options as the user just endlessly annoys me.
Fortunately, some games try to make the best of mobile touch screen’s strong points and increase interactivity. One good example is the classic Fruit Ninja, which utilities multi-touch and gestures, neither which work too well in the normal mouse-keyboard world. The result is much more satisfying to me, since I am not just dumbly taping the screen (albeit with perfect timing).
Another genre that I enjoy that has taken up a lot of popularity on mobile platforms is defense games (or tower defense games). These typically involve a setup period where you place your buildings and units, and then start the game to let the battle unfold. It’s fun to watch the action and cheer for your side, and the level of control you have is much higher than the click/don’t click style I discussed above. But a key point here is that the setup time is typically not timed and you don’t have to rush to place buildings and units, and once the hectic battle begins you don’t have to do much but wait (though sometimes you can upgrade or do other tasks). Again, comparing to full RTS games on the desktop where you can change the orders of unit’s in the heat of battle, I feel there is a loss of control and as a result less enjoyment. There are such full-featured RTS games on mobile platforms, but they are relatively rare and typically not given away from free.
Having tried a great many iOS games (most free and/or from one of the ‘popular’ categories in the app store) and being disappointed with the lack of rich, engaging controls is one of the things that inspired me to develop Play The Field. I took some of the basic aspects from the RTS genre and boiled things down to their simplest elements: creating units (of various types), moving them, and attacking. The important thing was that both placement and control of units happened during the game, in real time, so I was never forced to sit back and watch dumbly, or just slam the screen with some perfectly-timed pattern. To help things out, I took a cue from games like Fruit Ninja and added gestures for unit creation and selection to remove tedious machine-gun tapping.
I think the end result is fun and challenging, if you are interested try it out here: https://itunes.apple.com/us/app/play-the-field/id985621862?mt=8
(Image credit: Matt Trostle (creative commons attribution license): https://www.flickr.com/photos/trostle/6848810640/in/photolist-brcWN5-4UA6My-8QKFCa-bd88Ue-qpJH4d-4M6Jou-ehmy7i-bP2MWP-9rcj1f-5jKhPh-9m3Srr-5eYjSG-GaSJ6-7pAjno-4kAY89-89igMH-7rrg9h-9LiPpm-4pJmY5-9TSfwz-7pAVoS-8PcDor-b19MYk-kzUBDW-9mB2Sw-9sqQAA-Q2hEK-xULQW-dwDFBc-3Xmcvh-7eEbDP-4AAnR3-n9GwQ-CED3C-jKUF6d-6wqxxe-4ytp2-j1MjXi-7rVtoK-7pAXtY-dxHQfC-5Ftq8C-9vvgMv-eV5XK3-7pwv3K-bunSTi-7pAorY-bQPpYF-djDDRw-7F83fo)