Great demo. Look forward to the final release. It's nice for the red currency to still be relevant after the green currency, so it does not feel useless to kill red enemies. Gameplay takes a couple of runs to get used to, but feels very good very soon. Would love to see some non-power AOE weapons in the full release. Sound design is great, and the screen gets cluttered very fast which is quite fun.
The different enemies are also great design. Both the green and the weird chasing one. Makes you actually engage the game differently. Would be mindful if too many spawn in latter levels tho.
A couple of notes:
You should tell the player that from level 2, some enemies will actually harm you, as it's quite unexpected. Specially as the game starts with "the enemies cannot hurt you"
Also make it so at least 1 green enemy is guaranteed to spawn every run, so it's easier to pick up the early % green enemy spawn chance. This is specially relevant because the first few green enemies the player will likely not know how to kill yet, so won't get resources.
Finally if you can, add a tiny bit of story, to add to the mystery of progression. Small hints or conversations with the player that points to something larger is enough. Even small it tends to add a lot.
Good luck with the final release hope it succeeds.