I finally solved the issue with climbing on arbitrary mesh colliders!

You may have  noticed that you cannot climb every portion of the water pool walls near the top. That's because Unity Raycasts seem to have a problem with mesh colliders. What ended up solving this is using the spherecast, which for some reason doesn't have any issues with mesh colliders!

This goes a long way towards making the climbing system more robust.

I've updated the game, so give it a shot, and enjoy!

Stay tuned for more bug fixes, and other updates ;)