Damn, that's not even like 1/8 of the whole demo right now. After picking a key it should be present in the inventory.
Control scheme is straight from the way I used to play fighting games or emulated games. 'C' for jump is a compromise, I personally use 'left shift', it's super easy to use your ring finger but then you might get windows sticky keys activated. Cursor will be used soon, right now it just looks pretty.
I think I need to redo my first screen a little, people don't know they can climb platforms when jumping and holding up. There are 3 ways to cross to another screen but with missing key and no knowledge how to climb you're out of luck (or you can die in that screen to progress too, but you have inflated health to not die so it'd take a lot of time).