TWILIGHT 2000 (T2K) was a RPG of my youth. Growing up in the 1980's the thought of "going nuclear" was always there, though somewhat distant.
T2K owes much to Frank Chadwick. Mr. Chadwick made great miniatures rules, such as Command Decision, which clearly influenced T2K. Which means combat is the forte of T2K...not the RPG engine. T2K characters lack real dimension and the result is more of a skirmish game than an RPG.
But the setting! How do you use all that modern high-tech gear outside of a major war? T2K makes the post-apocalypse into the Middle Ages, where the players can be the heroes, just passing through or trying to settle down.
POSITIVE: Rich setting, combat
NEGATIVES: Lakc of real RPG character development.