Give the player one reliable gesture
Choose a gesture that fits the mechanic. Tapping is useful for selecting or timing; dragging can move a piece or aim; holding can charge a clear action. Avoid asking for a precise multi-finger gesture unless it is essential. If the phone will be held in one hand, keep the main target within comfortable reach and avoid hiding it behind the thumb.
Try a mobile-first prompt
Example prompt: “Create a short single-player game for a phone screen. Tap one of three large stepping stones to move a small lantern toward the visible exit. Each tap moves exactly one stone; a cracked stone ends the attempt. Show the next safe stone before the player chooses, and let Restart return the lantern to the same start. Keep the goal visible without scrolling and do not require holding two controls at once.” This is a proposed prompt, not an existing Oneshotgems title.
Check readability on the device
Play the generated version at the actual screen size and test the first action without zooming. Try the target with your thumb, then rotate the phone and repeat if both orientations are part of your intended design. Check that text does not disappear under the software keyboard or controls. If a target is easy to miss, enlarge or reposition it before adding more levels.
A mobile-target prompt describes design intent; it does not guarantee every device or browser behaves the same. Keep notes about the phone and orientation used so later revisions can be compared fairly.
Questions about AI mobile game maker
Should every mobile game use one-thumb controls?
No. Match the gesture to the mechanic and intended posture. A one-thumb layout is a useful constraint for a short action game, while a puzzle may work better with deliberate two-handed dragging.
How can I tell if a touch target is too small?
Repeat the same action several times without aiming carefully. If ordinary taps miss or cover important information, make the target larger, add spacing, or provide clearer selection feedback.