The only criteria I chose for this list is that all of my picks must have been designed with a computer system in mind as the primary platform, or be PC-exclusive. That means no console up-ports or simultaneous multi-platform releases! Oh, and they have to still be fun to play today, too.
As ever, keep in mind that this are my personal picks and no-one else's.
HM. Grandia II: Anniversary Edition (Game Arts/Skybox Labs, 2015)
HM. AM2R (Some awesome fans, 2016)
50. D/Generation (Robert Cook, 1991)
49. Jazz Jackrabbit 2 (Epic MegaGames, 1998)
persists to this day) and support for custom-made levels, giving it quite a bit of replayability. A solid exclusive title for PC proponents and still a fun platformer to this day.
48. Oregon Trail Classic (MECC, 1990)
47. MegaRace (Cryo Interactive, 1993)
46. Lemmings (DMA Design, 1991)
45. Shadowgate (Zojoi, 2014)
44. Team Fortress 2 (Valve Software, 2007)
43. Are You Afraid of the Dark?: The Tale of Orpheo's Curse (Viacom New Media, 1994)
42. Epic Pinball (Digital Extremes, 1993)
41. Ys Origin (Nihon Falcom, 2006/2012)