People have said this before, but using the Ctrl key for crouching is problematic. Way too many web shortcuts rely on that key, making crouched movement pretty much impossible. (The most egregious issue is that to crouch move forwards on a QWERTY keyboard, you need to press Ctrl + W, which also closes the browser tab.)
This could be resolved by moving the crouch button off of the Ctrl key or by making crouching a toggle action (rather than a holding action). Of course, another way of resolving the issue would be to release a desktop version, since those web shortcuts aren't a thing there.