I really like the art style of this game, but I spent the whole time battling the controls more than the game.
First, the camera controls are soooooo sensitive, which really negatively impacted how you moved because your direction depends a lot on which way your facing. I fell off a lot of things because I looked around too fast before I decided to just point the camera in the direction I wanted to go and then not touch them while moving. That is a real problem because it removes your depth perception in the 3d world. Especially since the edges of the platforms don't draw as lines when you're above them. I really wish that you drew edges of platforms. It made it hard to know where you could land.
I couldn't play with a controller. Mine, I think, registers with a slight permanent push down, which is fine in a lot of games, but because of the sensitivity, I basically just pointed at the ground and couldn't do anything. I unplugged it and then could play with the keyboard. I appreciated that you included it as a way to play.
I really like that it's non violent, since it seems like that is just a gimme in most games. However, the little grey guys are super frustrating. The fact that they make it so the player can't jump properly when they touch you is really frustrating, especially on the little tiny platforms you have to land on, you can't help it. You just sort of hope that they randomly walk away from you on that run.
Speaking of which, the second gem was almost impossible. It was so hard to land on the platforms with the little creatures. It would look like a good time to jump and they would just turn around and walk right up to the edge so I couldn't land a large percentage of the time. Or if I did land they would hit me afterwards and I couldn't jump. The second creature didn't seem to be quite as much of a problem, but I only got to it some of the time. I think its platform is a little wider and so it didn't essentially always knock me off. If I could have used the camera properly I would have had an easier time of it, I think. Also, if the creatures had a more understandable pattern, or stood still until you landed and ran at you after, I don't know, half a second. Something to make it so that when you could feel good about landing and then worry about the creature. Or maybe just making the platform wider. The third creature felt kind of like a slap in the face. Getting up that high and being so close to the gem and then getting knocked off felt awful.
I really liked that you could see the whole world from the start and that it opened up as you played. I saw the bridge at the beginning and thought it was need and hoped that I could go there. And then I could! It made my little bit of exploring at the beginning feel rewarded. The checkpoints were handled well, too. One at each gem and, importantly, one at the start of each section. Nice.
Overall, I think that with a few tweaks it wouldn't be so frustrating and would be even more fun than it already is!