Crash Bandicoot is an old-school platformer that is simple, yet fun and addictive.
The game that started it all, Crash Bandicoot, features a genetically modified bandicoot who must overcome the dangers and pitfalls of a tropical island to save his girlfriend from the clutches of his creator and nemesis, Dr. Cortex. The story is pretty simple and the gameplay is fairly straightforward. There's few if any puzzles in the game and most levels are very linear.
Unlike later Crash games, there's no portal system: you simply progress from level to level. The gameplay is similar to other Crash games, though a bit less polished and somewhat difficult at times.
Crash Bandicoot lacks the polish of its successors and is a bit hard, but if you're a fan of platformers, it's worth checking out.