Thanks for the feedback ad48! I really appreciate it!
I admit that level design is not one of my strongest game design skills and is something I am actively looking into improving. Thanks for pointing those level design based things out to me. I know that level design in general isn't easy, and going from 2 dimensions to 3 dimensions doesn't make things any easier, but I'm a big fan of 3D platformers, so I'm certain that I'll get it right one of these games.
The MeshColliders on the gates was a bit of an oversight. I did think of adding box colliers to them, but didn't want to go crazy with colliders as it would start to cause performance issues. In fact, I had originally had an open word type city level planned for the game (you can even see the music credit for it in the credits screen, as I forgot to remove it), but because it was so big and with so many colliders, even with mesh combining it started to crash my Unity so often (every time I tried to enter play mode), I had to scrap it. So, after that point I was a bit nervous about going collider crazy.
As far as Open-sourcing the game, i'd love too, but I can't. Most of the game was created with assets purchased on the Unity Asset Store. Aside from the Unity Chan model, loading screen artwork and the 2 tracks from the Unity Chan Album, everything else was purchased either on the Unity Asset Store or from SmartSound.com. Meaning that I have licences to use them, and I can't open-source assets that I purchased from a content creator, without their permission.
Again ad48, thanks for the feedback, as I believe that it will help me to make even better games in the future!