FTL! This game was probably my first introduction to roguelites back when I was still a wee little lad. Loved the space aesthetic, and the combat system was pretty unique for the time I thought. Runner-up would probably be Noita (roguelite trend here). If we’re including DOS era games, I’d add Centurion: Defender of Rome (predecessor to Total War games) and Sword of the Samurai (Mount and Blade but in Sengoku-era Japan).