The weakest of the trilogy, in my opinion. Instead of the world map being straight forward so you can progress at you own pace, it is instead a teleporter maze, making it very difficult to keep track of where you are and where you are going. The blaster pickups in this are even more confusing, because it uses the same sprites as the wall blasters, so you never know if it's an ammo pickup or a trap. Worst of all, it has the worst maze level of the entire trilogy. The other two games had mazes, sure, but they were small and contained to not overwhelm the player. This maze just goes all over the place, and has dead-ends that have just small enough of an opening that Keen can't get through. That's just bad level design to me. The boss fight with Mortimer McMire was fun enough, but the game surrounding it is just infuriating.