Thanks for trying out my game! I just pushed version 0.9.3 of the game which fixes a couple of bugs within the game. I'm still pretty new to figuring out builds with Unity and I don't have Mac or Linux devices to test them. However, I included separate folders for the Linux and Mac versions this time so hopefully, it works now! I appreciate you for notifying me about this and please let me know if it still doesn't work.
Also, I will take the player's speed into account. I'm still messing with enemy and tower mechanics and have been thinking of speeding the enemies up to pressure the player more as I am trying to go for a fast-paced gameplay. However, I do agree that the player is pretty fast though (I had to make the bullets go a lot faster because the player was outrunning them at one point!).
Thanks again for your feedback!