Thanks a lot for the feedback! 

I had no idea the MacOS did not work as it worked for a friend of mine.

The shooting indeed has a rate of fire which does not allow spamming, so it takes around 0.2s before you can shoot again and so far i have not had this complaint that it would not shoot. I've tested the game on multiple PCs and it works but i'll make sure to look into it.

That skybox is indeed bad :/