When you fire the pistol in Nuclear Throne, first of all the Pistol sound effect plays. Then a little shell is ejected at relatively low speed (2-4 pixels per frame, at 30fps and a 320×240 resolution) in the direction where you’re aiming 100-150 degrees offset. The bullet flies out at 16 pixels per frame, with a 0-4 degree offset to either direction. We then kick the camera back 6 pixels from where you are aiming, and “add 4 to the screenshake”. The screenshake degenerates quickly, the total being the amount of pixels the screen can shake up, down, left or right. Weapon kick is then set to 2, which makes the gun sprite move back just a little bit after which it super quickly slides back into place.