Survival

Overview
Survival mode gives you 3 extra lives and no time limit. You are awarded an extra life every 10 levels. Each level takes more experience than the previous one so by the time you are level 30 it can take a very long time to get another life.

Tactics

 * As you have infinite time you can afford to wait for the number of enemies in the arena to increase before you open fire. The more enemies there are the bigger your combos will be.
 * You will get ambushed frequently by enemies spawning in a ring around you. Ambushes are preceded by an alarm sound.
 * Some Ambushes spawn around the edge of the arena. Don't stay too close to the walls or you won't get much warning.
 * The best way to escape an ambush is to pick a direction, aim you guns that way and just charge forwards trough the opening you create. Once you're safe you can mop up the rest.