Rush

Overview
Rush gives you infinite lives and a time limit like Crunch Time however each time you die you will lose some time and every time you level up or kill a Cube you gain some time. This results in a precarious balancing act where you have to balance scores against survival.

Tactics

 * Trying to level up as fast as possible to grab some time early on is key. It takes more XP to gain levels each time you level up so make the most of those fast early level ups.
 * Cubes spawn on a timer roughly equivalent to how much time they award. Killing them as soon as they appear will net you enough time to get to the next one with a couple of level ups in between.
 * Make sure you grab all the dropped XP pickups. It might seem safer to let them expire on the other side of arena but they could mean the difference between a time extend or game over.