i know most will go with TW WH2, DOW, SM2, or maybe some even Rogue Trader or Vermintide 2.
but any Mark of Chaos fans?
Warhammer: Shadow of the Horned Rat was an all-time fave of mine though so MOC getting a TW-esque treatment again in the 00s was pretty awesome.
that said, if you really wanna go with a cult classic you gotta with the epic Final Liberation WH Epic 40K, or the classic WH: Dark Omen.
honorary mention to the permadeath XCOM clone WH40K Fire Gate or the terror and tension of still maybe the only game to make a single space marine feel like a terrifying, unstoppable boss fight when you are just a lowly infantry lol – – WH40K Fire Warrior.