Write the prompt around a playable rule
The prompt makes character abilities distinct and introduces a simple coordination task. Show which character is active and where the inactive one remains. A door should visibly respond to the floor switch, while vents should look passable only to the lantern. Start with a safe tutorial room where players can test each ability separately.
Original concept prompt: “Create a solo platform puzzle with a small fox and a floating lantern. Tap to switch control. The fox can jump across gaps; the lantern can pass through narrow vents and activate light-sensitive doors. Reach the exit by parking one character on a floor switch while moving the other through the opened route.” This is a recipe for an idea, not a claim that this exact game is already playable.
Play, observe and refine one thing at a time
Move the fox and lantern through their individual obstacles, then try the floor-switch sequence. Check whether switching is immediate and whether the inactive character stays where expected. If a door closes unexpectedly, show which switch controls it. If the fox can complete every route alone, make the vent or light gate require the lantern’s specific ability.
Add one obstacle that combines both abilities after players understand them separately. Keep switch timing forgiving at first. If the inactive character is hard to track, add a marker or a small portrait indicator. Replay the coordination room after changing one ability to confirm that both characters remain useful.
Do not make the inactive companion disappear or move unpredictably. Their position is part of the puzzle state. Keep the switch control obvious and ensure the player can see the effect of each ability before committing to a difficult jump.
Playable reference for this prompt: Jelly. A wobbly jelly block slides toward walls with cut-out holes; drag sideways to morph it tall-and-thin or wide-and-flat so it squeezes through each gap. Use this example to compare the proposed rules with a game you can try now. For your version, use this check: How do I show which character is controlled?
Questions about companion platformer prompt
How do I show which character is controlled?
Mark the active character clearly and keep the switch action consistent. Test changing control while one character is on the pressure plate.
Should the parked character keep holding a switch?
That is the intended coordination rule here. Confirm it remains true after switching control and when the other character passes through the opened door.