Mobile Game Design: Thumbs, Battery, Thermals (2026)

Q: How big should touch targets be in a mobile game?

Apple's Human Interface Guidelines for game controls ask for frequently used controls of at least 44x44 pt and less important controls, such as menus, of at least 28x28 pt on iOS. Google's Android accessibility help recommends touch targets of at least 48dp wide and tall. Treat both as floors. PawScooty's action buttons were about 62 pt after its first playtest scored ergonomics at 5.0 out of 10.

Q: How long should a mobile game session be?

Design the smallest complete unit of play to fit a gap in someone's day, which usually means a few minutes. PawScooty's first level is a 2,160 m route timed at 180 seconds, and its production plan caps a successful run at 240 seconds. The more important rule is that the game must pause, save and drop queued input the moment the app loses focus, because the player does not choose when a session ends.

Q: Why does my mobile game slow down after a few minutes?

The usual cause is thermal throttling. A phone has no fan, so after several minutes of heavy load the operating system reduces CPU and GPU performance to protect the device. Short benchmark runs on a cool phone will not show it. Profile the heaviest part of your game for at least 15 minutes on a physical device and record p95 frame time and thermal state, not the average frame rate.

Q: How do I read the thermal state of a phone from my game?

On iOS, ProcessInfo.thermalState reports one of four cases: nominal, fair, serious or critical. On Android, the ADPF Thermal API, released with Android 11, returns a thermal headroom value from 0.0 for no throttling to 1.0 for heavy throttling. In Unity, the Adaptive Performance package wraps both behind a thermal event with warning levels of NoWarning, ThrottlingImminent and Throttling.

Q: Should a mobile game run at 30 fps or 60 fps?

Unity's scripting reference says that on mobile the default target frame rate renders at a fixed 30 fps to conserve battery power. Raising it to 60 doubles the frames you draw for the whole session. My preference is 60 fps for action play while the device is cool and on good battery, dropping to 30 when a thermal warning arrives or the battery is low, and 30 on static screens such as shops and menus.

Q: Can I test heat and battery behaviour on a simulator?

No. A simulator renders on your computer's hardware and has no meaningful thermal state. PawScooty's notes record the iOS Simulator at roughly 30 fps and label it a host-bound trend metric only. Heat and battery testing needs a real phone, ideally the oldest model you support, with a case on if your players use cases, running an unbroken session of 15 minutes or more.

Q: What happens to my game when the player turns on Low Power Mode?

Apple's documentation says Low Power Mode reduces CPU and GPU performance, lowers screen brightness and pauses discretionary background activity. Your game can read ProcessInfo.isLowPowerModeEnabled and respond by capping frame rate and trimming effects. On supported Android 12 and later devices, the Game Mode API tells you whether the player chose standard, performance or battery mode, which is a direct statement of what they want.

Q: What is a slow session in Android vitals?

Google's Android vitals documentation describes a slow game session as one in which a significant portion of frames, more than 25% in its example, fail to meet a target frame time such as 50 ms per frame, which equals 20 fps, or 34 ms per frame for 30 fps. It is a games-only metric, and it gives you a published yardstick to design your minimum device tier against.

Satyam Kumar

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Designing Games for Mobile: Thumbs, Battery, Thermals and Short Sessions (2026)

By Satyam KumarNovember 15, 202613 min read

mobile game design thumb zone touch target size one-handed play short session design thermal throttling unity adaptive performance unity mobile optimisation target frame rate mobile game battery drain android adpf thermal headroom ios thermal state low power mode android game mode p95 frame time safe area layout pawscooty indie game development

Designing Games for Mobile: Thumbs, Battery, Thermals and Short Sessions (2026)

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Satyam Kumar

Founder & AI Architect, AppScale LLP

AI & Cloud Architect. Helping teams build systems that scale to millions.

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Designing Games for Mobile: Thumbs, Battery, Thermals and Short Sessions (2026)

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