Haha thanks for the detailed feedback.
Yes I feel that the mouse sensitivity slider was a very crucial thing that I forgot to implement. Also, cursor.lockmode -> confined was something I forgot as well.
Yep, the sounds were a last second addition, and the intro sound was left looping and hence plays after every few intervals. I need to get better at sound design.
The difficulty progression is what I like the most. While it is not as complex as that, I really love Valve's Left 4 Dead 2's AI director, who adjusts the difficulty to you, in a more complex way tho. It allows all people to enjoy.
Thanks.