I honestly never thought it'd be possible for a 2d platformer from the near-late 90's to have a great atmosphere, but hoo boy, does it nail it well. While it definitely does show its age, Abe's Oddysee is still a wonderful adventure/puzzle platformer that's sufficiently challenging while not being incredibly frustrating. Though, you're probably going to wind up getting the bad ending on your first run; there's a lot of secret areas in the game, and if you're aiming to rescue ALL of your fellow workers, then... well... good luck to you. Plus there's the matter of all the cute-but-ferocious critters aiming to eat and/or shoot you.
Of course, there's the appeal of the upcoming New 'n' Tasty remake that will present the game in stunning 3D, but if you want a throwback to the PS1-era past before then, you've come to the right place.