Tempest

This is the easiest achievement in this game.

First of all, you need to decide if you are a completionist or not. If you are, this game is HARD to get any gamerscore at all in so take that into consideration!

Clearing the first five waves in 90s sounds difficult but is actually pretty easy. Enemies will tend to concentrate in certain "sectors" of the tunnel so strafe back and forth of those areas while spamming the fire button. When the enemies are cleared out, move on to the next enemy-filled area. You have one superzapper (smart bomb) per level so make sure you use it. The best time for this is when you've been clearing enemies on one side of the board and the other side has had time to accumulate a bunch of them. You'll also want to make sure you take care to avoid the spikes as you exit the level. Dying doesn't affect the achievement but it's probably 5-10 seconds of wasted time that you can't afford.

Remember that you have to CLEAR level 5, not just get to it, for the achievement.