Let's Go!
The graphics are pretty grainy, but are somewhat cartoon in a good way. The explosions of lemmings is always fun to watch. Surprisingly, though, the game has to slow to to render a mass execution of lemmings. Well... that's not bg fault. There are many ways to solve each level and skill and pure ingenuity is your talent to figure them out.
Great fun, lasts forever. Easy enough in the beginning so you can learn how to play. Has a ton of levels, I don't think anyone could ever really finish the entire game (in less than a few months at least). And the difficulty can get insane in the final levels. Use cheats if you want to skip to a certain level.