Functional, mostly. All the commands respond as you said they would. Targets fall briefly when hit, but only if you were aiming at it when you held the trigger down. If you want to spray n pray, no targets respond. If you press and hold the trigger on sniper, the muzzle flash remains onscreen for as long as you hold the left mouse button.
Sound would be nice, but I'm assuming that was left out considering where it is in the dev phase. Keep at it, looks like a great start!