This is a cool little game and there are some nice systems at play. This genre of game is always fun to make, and the gameplay loop can be very addictive.
Here is my feedback (Going from most important to nitpicking):
- Having a description of how to play the game will help players to understand what to do because I had to click on everything to figure out where the upgrade menu was. (This could even be something like an 'info' button in the pause menu)
- There is no pause menu.
- Being able to press a key to open and close the upgrade menu would also be nice. (I had to click on the square next to the fire icon to open the upgrade menu)
- The typeface chosen works well for headings and bigger text but does not read well when displayed at smaller scale. (e.g., the ability descriptions)
- Adding something like a wave counter or timer could help the player with reaching a goal because now the player is just killing but to achieve what?
- The sounds of the enemies dying gets repetitive quite quickly. (varying the pitch every time could help with this)
- The pixel size of the assets used are not consistent. (e.g., the player character sprite vs the mushroom sprites vs the environment sprites)
Possible Bug:
- When I clicked on the upgrade menu the wave ended, or something else maybe went wrong, because I could not exit the menu without going to the next wave. (I clicked on the square next to the fire icon to open the upgrade menu)