welcome to TIGS Hare and interesting game you have here!
From the nature of the demo's visuals and sounds I'm guessing these are mostly placeholders at the moment so I'll hold back from commenting on them. I did notice a couple of things though.
It seems like it's difficult (impossible maybe?) to reverse direction during a jump; for example, if you jump for the first platform you come across in the Proving Grounds. I can see the appeal of perfect placement for the jump-off point but as player I much prefer being able to control mid-air velocity.
Second during combat it seems easy to fall into a negative feedback loop where you get hit and the knock-back/stun sets you up for another hit right away. If the stun time was shorter I don't think this would be such a big issue but as it is it can be impossible to just retreat when you start getting hit.
I don't know if you're planning to keep this at all but if not please consider removing the sound alarm when you have a low resource, it was pretty annoying. Maybe some other kind of visual feedback?
I like the variety of offensive/defensive weapons, the free roaming levels, and the resource spots. The combat feels good overall too except for what I mentioned above.
Looking forward to more of this!
(also could you package everything in a folder inside your zip?)