A casual game is one you can put down. That is the whole definition, and it says nothing about depth — several of the deepest games ever made are playable in twenty-minute pieces, and some of the shallowest demand an evening.
Whether stopping costs you anything. If leaving mid-session loses progress or breaks a streak, it is not casual however simple it looks.
One session is fifteen minutes; the game underneath will take a hundred hours to exhaust.
No fail state, no timer, no way to fall behind.
Games you can hand to someone who does not play games and have them understand it immediately.
That you can stop without losing anything. Short sessions, save anywhere, no punishment for a week away — none of which has anything to do with how deep the game is.
Balatro, Slay the Spire and Into the Breach are all playable in short bursts and all have ceilings people are still climbing years later.
Often the opposite. A lot of them are built around daily timers and streaks, which means stopping does cost you — the thing a casual game is not supposed to do.
Start from something specific rather than from the genre:
Or by the machine you own:
Or start from a game you already love — every title we cover has a page of hand-written recommendations, and the best-games lists cut the same library by era, audience and mood.