Every other game does it, when you're crouched and you press space, you should stand up.
I don't know if it's by design but weapons with 2x scopes feel like the recoil is uncontrolable, whereas if it's attached with a 1x scope, it has nearly no recoil (I felt that with the m4 I think).
I don't understand the different sensitivities. I like it simple, like cs go. I have my sens and the zoom sensitivity which is a multiplier of the general sens. In Sandtorm, scope sens are set too 0.6 by default, and I don't know what this means. Could you make that clearer ?

Couple of bugs : right click when spectating doesn't work
Pressing enter or esc in the main menu doesn't work sometimes (azerty keyboard)
Optimization but I understand that you're working on this