Gunpoint's a neat stealth/puzzle game about hacking stuff and jumping through windows (very little actual holding people at gunpoint though). Being of that genre, playtime could vary a lot, especially if you try to be perfectionist, but it should be doable in a day. Great jazzy soundtrack too.
Jazzpunk is a weird comedy game, essentially FPS exploration levels with various comedic gags peppered throughout. Again, playtime can vary depending on how thorough you are about checking every single corner for something, but it probably wouldn't take more than say 3-4 hours. Obviously your enjoyment will depend on your sense of humor, but I found it pretty hilarious
Linear FPS campaigns are a good candidate in general, older games could be decently long but there was a period where 5-6 hours (and sometimes shorter) became a pretty common length.