Gin Rummy Classic

Building sets and runs before your opponent does is the whole idea, and gin rummy has stuck with that formula for decades for good reason. Gin Rummy Classic plays it straight against computer opponents with a few distinct styles, so a cautious AI feels noticeably different from one going for a quick knock. There's no twist on the format here — just two-player card play as it's traditionally done, watching discards for clues about what your opponent's holding.