Island section:
Instantly liked it for being an island. TTS voice is a nice touch. Pirate has too much health.

Race section:
Racing is fun. trigger_push lag makes lap 3 really hard. The 15-second music loop can get irritating, but you can turn the volume down in options.

Coin section:
I've always wanted something like this. It felt like a reward after lap 3 of the race section. However, something is off with the coin hitboxes. Better if the hitbox is too big than too small, if that's what the problem is. A gauss gun would be fun.

Scientist section:
No idea what was going on. It all went so fast. I'm relieved we weren't forced to understand it. I later learned we had to listen to the VOX voice. I usually ignore that thinking it's background noise, and it's often hard to hear/understand.

Colored block section:
I thought I would like this as a bunny hopper, but there's some horrible collision problem on the blocks. I sink half-way through on each hop (180ms ping). Maybe the collision models are null-textured or EF_NODRAW'd (not predicted client side)?

Barnacle section:
Wasn't sure what to do here. Someone else solved/cheesed it before I understood. Seems like you have to hop on the trigger_push area while grappling to get past the first part, which is hard with lag.

Dice section:
Looks nice. Puzzle needs a hint or some feedback that you got a pair of sides correct (all pairs of opposite faces on the die need to add up to 7). Randomly pushing buttons worked eventually.

"Sterilized" section:
Good co-op idea, but I was confused on what to do for most of it. At least there were monsters to shoot while others were figuring it out. Nicely mapped.