The game is fun and I imagine with some extra polish and work could turn into a solid game on steam however the significant ramp up in difficulty from wave 2 to 3 cought me twice and I couldnt really see how I would get past it.
The visuals look really nice although I imagine due to the deadline the enemies didnt get a custom model which might be a starting point for future improvements. Additionally I think possibly minor things such as the tutorial frame could get a bit more polish.
The sound design is really nice and I think currently it includes everything necesarry and a bit beyond.
The concept is nice however considering the theme is about everything being a resource I would have expected the rocks and possibly trees to also be a resource, and possibly the enemies in some way.
For future improvements I would suggest making so the enemies on death drop some sort of healing orb (or anything else to somehow turn them into a resource), to maybe add a warning for when the next wave starts and somehow making the larger amounts of enemies surmountable (possibly be adding a turret in some way made from the rocks and trees).