Great demo, looking forward to full game. Few tips:
- In upgrade tree, I needed to refund some stars, but I didn't remember which upgrades did contain them (if upgrade is maxed, information about it's price type (triangle, star, hourglass) is hidden). I needed to refund it one by one to find out. Maybe type (and maybe amount) can be indicated somewhere in upgrade box - either next to "Max" text, or next to whole upgrade cube on upgrade tree?
- Add possibility to sell towers
- Right click to tower upgrades it
- Upgrade for auto-collecting coins (or maybe auto-collect coins by default?)