A few suggestions here,
- First, the game is pretty smooth to play which is a good plus point.
- The concept seems to be pretty good and has the potential to be great if done well.
- IDk for some reason, we found it difficult to play on start as the difficulty is high from the beginning itself, making the game progression slower.
- The cooldown concept can be bumped up even more with the particle system and a lot more effects to make the game feel dynamic.
- The sounds and the graphics could be polished ahead for impactful gameplay.
- For the future, you can plan for making it a multiplayer game as it's fun to play with friends.
- Adding more powerups in a meaningful sense would be great.
- Yeah, the diamond is definitely confusing as for most of the games it is kept as a collectable. For this game the way it's kept in the middle don't at all look like it's a decorative piece. So, consider changing that.
- You can do a lot of stuff visually and can make it action-packed.
- This game has the potential to perform well in the Mobile market, so stick to that and move ahead.