To beat each level, you'll have to fight tons of enemies who want to shoot you or even kill you with their bare hands.
Luckily, your character has the same guns as his enemies. That said, although you can use your weapons, the hand-to-hand combat is usually much more effective for getting rid of the bad guys.
Remember you only have so much time. If the clock runs out, you lose... and the world ends.
Agent One is a very short and entertaining 3D action game with surprisingly great graphics. It was single-handedly developed by an indie programmer in under 72 hours.