The Basics: Click and drag on the towers to place them. Make sure you can afford each one. Get money by killing zombies. Towers: Turret: Deals one damage and can be purchased for $10 Spitter: Shoots very fast but can only damage the boss. It can be purchased for $5 Trap: Doesn't shoot. Can only kill basic zombies. It can be purchased for $5. Healer: Doesn't shoot. Adds +1 hp to your total health every 30 seconds. It can be purchased for $50.
My friend was making their own tower defense game and it kinda inspired me to make my own. I'll put a link to his game here once he's finished: