What the… Zombies!

Arrow keys to move, space to shot, F to stab the zombies, Q to select what you want to build, H to heal (if your health isn't at max), B to build, hold left shift to run (if you're moving) and that's it! If you need to see this again, there is a help menu on the pause screen, wich you can acess clicking in the button on the top left corner.