In Robocraft, you can play in two very different modes: construction mode and combat mode. In the first, players create their own robot using blocks (the way you build is very similar to Minecraft). But, in order to use certain blocks, you first have to unlock them from the technology tree, which you can only do by playing.
Once you've created your war machine (which could be a jeep with a machine gun, an armored jet with lasers, or even a Bart Simpson robot) you can start fighting. During combat, players can move themselves in any direction they want through immense levels while trying to destroy the players that appear on the screen.
It's very important to keep in mind that getting hit by a weapon will cause actual damage to the structure of your robot. In other words, if someone hits your engine, it's possible that your vehicle will be immobilized. Likewise, if you can hit knock an enemy's weapon out of its hands, you can leave him defenseless.
Robocraft is a fun multiplayer action game that's unique and free to download. And that's a strange combination nowadays.