Now while I consider myself more of a Jazz Jackrabbit 2 fan, due to its excellent multiplayer experience, I nevertheless prefer JJ1 when it comes to singleplayer. Everything from the gameplay, to the level design and the great soundtrack is at the very peak of what the 90's platformer era had to offer.
A wonderfully fast paced platformer, with exceptional gameplay. While the official single player levels leave much to be desired (but the community on www.jazz2online.com has remedied this shortfall!), the online gameplay is incredibly fun. Imagine a 2d version of Quake 3, fast paced on the one hand, on the other you need to control key pickpups on the map, get into your opponents head and outwit them etc. It's great to see the game on GOG and it's great to see the community keeps evolving the game and adding new levels to the mix.