Select the track and difficulty you want. In the game, buy your towers from the sidebar on the right, then place them around the track to maximize their effectiveness. You will unlock new tower types with every new rank you earn.
You goal is to kill all the insects in each level. Build your tree out and up and place weapons on the trunk and branches to fend off the invading insects. Your weapons will not fire on insects once they've landed on your tree's trunk, so spread out and place weapons with that in mind.
A classic block breaker with a fun twist: shooting! Moving the mouse moves the paddle and crosshair. Bounce the ball using the paddle and shoot falling blocks with the left mouse button to gain points.
Classic Snake with a delicious advanced mode. Eat all the food being thrown onto the playing field, and do it fast enough to increase the points multiplier. Every time the multiplier reaches a multiple of 10 some fruit appears. Eat the fruit for more points.