I really like the mechanic of having a little helper that does multiple things, especially because you can't use it for e.g. light when it's a platform. I think there's some interesting things that can be done with that.
I felt like Timmy moved a bit too fast for how little you can see ahead of you, even with the light out front (the size of Timmy relative to the screen essentially massively limits how much you can see more than the darkness). I also would have liked to be able to move the light guy up and down without sending it forward (e.g. at that second upwards platform before the spinny thing, it needs to be a bit higher, but the forward distance isn't that much).
Controls wise, I usually prefer having movement and jump on different hands, which made P for platforms a bit difficult to use, but that might just be me. Also, the arrow keys that are given as an option early on work for movement, but not the light orb controls?
Overall, an interesting concept hampered somewhat due to controls/platformer physics.