Dude, the fuck? I'm no expert at video games, but that whole game was a cakewalk, yes even the last level. Maybe I was at my "gaming peaque" so to speak when I played through that.

Well, I remember I was a scared about the last level, since everyone complained about it, but I personally didn't find it that hard very much when I reached it. TBH, last level was the only part of the game that provided a little bit of challenge which is a good thing. 
But there are two things that I didn't like about the game.  
First, it was how hard some figments were to reach. For example, I remember spending half an hour in the levitation ball race level to get a single piece of figment which was very annoying and boring and I had to use walk-through in the end. Since most of the figments are along you way and there's no problem reaching them, it's kinda annoying to see that some of them are so hard to see and find.  
Second, it was the very disappointing bonus movie that got unlocked by reaching the highest rank ( 100 ). It wasn't truly worth the effort at all. I though it's going to be something awesome.  
 
But except those two little things, I believe Psychonauts is the best platformer I have ever played ( there aren't much platformers on PC though ) and I think everyone should play it. 

AAAGH! ZOMBIE THREAD! RUUUUN!!!!

It has incredible charm, atmosphere and characters. There's a PC demo around that can help you check out if you agree with my (and quite a few other people's) opinion on that. As others have said the gameplay is more standard platforming than anything mindblowing but I enjoyed it greatly still.

Like many other games it gets more challenging over the duration of the game but nothing I got hung up on too badly. For some reason I finished Meat Circus in something like 3 or 4 attempts overall and I'm not a platforming expert by any means. Maybe I lucked out or the PC version lacked some issues the console releases had since most people complaining seemed to have played it on console. I don't know that for sure though. I'd say don't let the notorious ending stop you if you enjoy the gameplay and setting. It might be just backlash to a hyped game (in some circles), a rumor everyone repeats now or inconsistencies between different versions. I could never figure out what those complaints were really about since I never heard a specific description of what is supposed to be that outrageously difficult.

I enjoyed the game soooo much.

The last level was frustrating, sure, but it didn't feel too bad for me... and I was playing with a mouse/keyboard combo, wich is not ideal.

I also liked that there was a lot of stuff to do and find in the hub world. Most people seems to hate searching for hidden items, though.

Anyway. I think the gameplay is pretty good, if a bit janky in spot.