Very nice demo. I'm definitely looking forward to the release version.
If it's okay I'd like to leave some suggenstions though.
1. Visual feedback for taking damage could be more prevalent.
2. Melee enemies.
3. Maybe add like different tiers to the colors. Like a special 2x damage red. With the clolor theme in mind you could call it it crimson red or something.
4. Not sure if I saw that correctly, but can you block projectiles with the melee? If yes, that's pretty cool, but would be nice to have in the tutorial rooms.
5. Effects for the character like higher movement speed.
Two more smaller things: Enemies somethimes seem to be stuck in the corners of the rooms and stop attacking and also please let me use esc to close the map.
In the end I'd say: Although there is quite a bit of room for improvement, it's just a demo so that's to be expected, but it's still lots of fun already. Keep up the good work!