It's a really very pretty game, there are some nice art assets that remind of me Prince of Persia, but I think I would best describe the 2d-3d transition experiences transitioning from a cool 2d platformer to a different completely unrelated 3d game. It seemed to serve no practical purpose and the angle of the 3d camera was really poor so the transition felt like someone just stole a nice side scroller from me I was enjoying and made me play a 3d Playstation game with awkward controls.
Don't feel bad about it though, this sort of 2d to 3d transition have been tried for years even by triple AAA dev companies and it rarely works out for them. It's tough to pull off. If I were you I would scrap the 3d portion and work on making the 2d side scroller more balanced and faster. Maybe with some way to block or repel enemy fire. I would like to be able to jump a little higher to reach some of the platforms. Above all else though.. speed, Prince of Persia style. Like I think this is a really cool game that just needs to be so much faster and you should be mowing through enemies by the dozens.