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, available verbs and 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 also leaves more production time for tuning, feedback and accessibility instead of maintaining a sprawling feature list.