There are a lot of things to love about Twilight: 2000 (paid link) but one of my favorites is its hook (one of the best hooks in RPG history): The PCs, all soldiers, are stuck in the middle of Poland after five years of global war, including exchanges of nuclear and biological weapons, and then, “As division headquarters was being overrun, the CO’s last radio message was, ‘You’re on your own. Good luck.’”
From character creation (random stats balanced by time spent in combat) to coolness under fire, random encounters, and a deadly combat system that makes every firefight something to be wary of, the rules are delightfully old-school and spartan in their presentation. Combat is detailed, but my memory of playing T2K 15-20 years ago is that one firefight cements most of the basic rules nicely.
I want to run T2K as an alternate history sandbox, exactly as presented: In its version of reality, 17 years ago looks like 1984’s take on what was then the future. “You’re on your own. Good luck.“