Start quickly, not abruptly
A snack-sized game should reach its first meaningful decision within seconds. That does not require dropping a player into chaos. It requires a menu that remembers settings, a tutorial that teaches through action and a restart that happens instantly.
The first room or puzzle should communicate the goal, the available verbs and the success state without a page of text.
Make one session complete
A five-minute session should end with something resolved: a puzzle solved, a short run scored, a room mastered or a meaningful checkpoint reached. A game can be long overall while still respecting a short play window.
Autosave, pause behaviour and clear level boundaries are part of the design, not administrative extras.
Depth comes from combinations
The best compact games reuse a small ruleset in surprising combinations. One new tile, hazard or constraint can transform familiar decisions without requiring another tutorial system.
That approach is also practical for a tiny studio: more attention goes into level quality, tuning and feedback instead of maintaining a sprawling feature list.