Two shapes of casual game
The gentle ongoing world. Stardew Valley and Animal Crossing are the two great examples. Each in-game day is short, there’s always a natural stopping point, and nothing bad happens if you disappear for a month — you pick up exactly where you left off. These suit someone who wants a small, pleasant thing to return to rather than a story to complete.
The instant session. Mario Kart, Switch Sports and a retro collection all work on a different principle: you switch on, play three rounds, and switch off. There’s no progress to protect and nothing to remember, which makes them ideal for a genuinely unpredictable schedule — and ideal when someone else is in the room and wants to join in.
Short games are underrated as gifts
There’s a persistent idea that a good game must be enormous, which is exactly backwards for this person. A game like Unravel Two that finishes in a handful of evenings is far more likely to be completed and enjoyed than a hundred-hour epic. For a busy recipient, a short game is a feature, not a compromise — and the sense of having actually finished something is a large part of the pleasure.
How this differs from a beginner
Worth separating, because people conflate them. A beginner needs a game that isn’t too hard. A casual player may be perfectly skilled and simply needs a game that fits into a short evening. There’s overlap, but if the person you’re buying for has played for years and just doesn’t have much time, you want this list rather than the one for beginners — difficulty isn’t their problem.