Very good concept that has potential. Personally i think difficulty was a little too much mostly because of the smoothed gun movement while yes that is cool gameplay wise its not fun (especially when reloading)
Also since there was a simple tutorial explaining what the goal was, having a textbox saying you can switch weapons would be appreciated! i only realized during the second playthrough and during my first i had to use only the sniper!
Other than that very good game and with some adjustments it can be very fun!
edit: forgot to mention there was a bug where the next wave never started resulting in a softlock. This only happened once however.