Midway through Cave Story, near the end of the Labyrinth, there is a room with a single door placed across a large gap. After entering the room, Professor Booster falls from above and lands offscreen in the pit below.

If you jump down and talk to Booster, the Professor will die after giving you the Booster 0.8 jetpack. This will also make the game’s best ending inaccessible.

For the best ending, you need to jump over the gap and leave Professor Booster behind to fend for himself. Later Booster will appear alive and well in Mimiga Village with an upgraded Booster 2.0.

Is it ever explained how Professor Booster survives the Labyrinth if you leave him behind?

  • 2
    My theory is that the Professor actually faints instead of dying. And since he gave you the Booster, he no longer has a way out.
    – Nolonar
    Commented Nov 27, 2017 at 21:33

5 Answers 5


I'm not able to confirm this at the moment, but I seem to recall text in the original translated script that implied that since you don't drop down there and he wasn't able to pass on what he knows and his work (the Booster 0.8) he rallied enough to use the booster tech to get out of there, either by finishing the booster or by using the parts of the booster which he then put back together and improved later.

It's less that Professor Booster needed assistance to get out and more that when you drop down there he passes on everything he can because he thinks he's a gonner, when he could have survived provided he still had access to the booster he gives you.

  • This is really the only thing that makes sense. Well said. Commented Nov 23, 2022 at 18:10

The game itself never explains it, but the most reasonable answer is that if Quote jumps over the pit, Prof. Booster uses the Booster v0.8 (because he never had to give it to Quote) to get out of the pit. Afterwards, he would go back to the clinic and get healed. Also, he would go back to the pit and make fixes to the teleporter, giving him time to upgrade the Booster v0.8 to the Booster v2.0. He gets back to Arthur's house just in time to give the Booster v2.0 to Quote. This also explains the fact that if Booster doesn't survive, you can't use the teleporter to go back to the Labyrinth.

I rest my case.


No, there is no explanation offered in game. Presumably he used the booster to lift himself out of the pit, then made his way back to the teleporter and made some last minute changes to the booster before giving it to you. Maybe he was rescued by someone else with more medical knowledge. Unfortunately, we have no way of knowing for sure.


Although there is no in-game explanation, it's like a Schrödinger's cat syndrome: If you go to see him, he will die because of injuries. But if you don't, then he will live in-game, as if you took an alternative storyline where he survives.


He just fixes the teleporter that was farther below and that's it...

  • 2
    Then why would he die if you talk to him?
    – Stevoisiak
    Commented Dec 14, 2017 at 21:54

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