MechAssault Walkthrough:
Size Matters

This is a fun one! You are in an elemental. i.e. you're VERY tiny. You must go find the mech base in a little elemental outfit. Go across dodging enemies and around grid walls. Head in through the gate which opens. Now you reach a lava floor - hop across the islands.

When you get to the mech area, you're told "stop window shopping - the atlas will do fine."

MechAssault Walkthrough, Tips and Techniques