Space to fire, hold space for rapid fire. Use your mouse to aim (your mouse is kind of like your crosshair), and defeat all the dinosaurs. When you run out of ammo, press "R" to reload. Takes a second or two to do so, though. Don't press space while reloading though, that glitches out the whole game, I don't know why. But, I'm working on it. Dinosaurs may appear in random places. Takes a few shots to actually KILL a dinosaur. Game gets harder as you go on.
Looks "OK" in full screen, recommend regular screen for better look. There were tons of remixes of projects I got things from, so, I guess I'll just thank those who made Pixel Guns here on Scratch and Pixel Dinosaur Sprites. Will be adding more sounds, dinosaurs, There ARE HUGE BUGS AND GLITCHES, sorry. Thanks. UPDATE: ADDED TRICERATOPS + UTAH RAPTOR