I did the "questionable area" last night. While the platforming has plenty imagination, it lacks polish and precision. It's functional, but not all that fun and sometimes a bit frustrating with the camera and being able to see where you're going to land. I'm more tempted to use a fast travel hatch than 'platform' back, while in a Mario game or even Prince of Persia games I would never consider that. Ratchet and Clank has better platforming segments.
It's always been like that with Double Fine. Top notch in the art department, creativity, characters, dialog. Gameplay always feels a bit added on. Which is fine, less distractions from what the game excels at. However if you're not interested in story and just pick this up as a platformer, the game play won't leave a lasting impression. Which explains the 7.0 user score on metacritic.
My only 'gripe' with it (apart from the camera) is the ability mapping. I have more than 4 keys on my Keyboard.... Very annoying you can only use Q, E, R and mouse to assign max 4 abilities at a time. This way I never get used to what button does what. Fail.
I guess it's a different design philosophy. I imagine Mario games start with the course design, the game play, set to a theme (abilities to use) Then when the game play flows, the scene gets fleshed out, dressed up. It looks like Psychonauts 2 levels started with the world design, then the platform bits got fit in afterwards. Hence jumps that aren't always spaced out correctly, the camera getting behind stuff or having to wildly zoom in and out, awkward turns and match ups, not suitable for speed running.
Ratchet and Clank has the luxury to do both, since it can fall back to shooter arenas when platforming doesn't fit all that well in the scene. And sometimes it switches to cut scenes or long grind rails to tie things together. Mario games are all platforming first, world building second. The worlds all look made for / around platforming. Psychonauts 2 feels very much world building first, platforming added in where possible.
Btw, I spend 10-15 minutes trying to get up the inverted waterfall. It looks like you should be able to jump on the logs that go up and a few times I did. But you simply die. Is it not possible? I tried frogger style staying on the logs from where they start on the river, jumping onto them from the side while going up, and hanging on the edge. You simply die halfway up.
