Rusted Moss - Sister Rivalry with barely any upgrades 

Achievement hunting and being stubborn is not a good combo.
If this does well maybe I'll do the boss again with no upgrades and only one gun.
If you are looking for a guide to get to Maya 2 use this video
• Rusted Moss | Sister R...
But instead of instantly going to the portal, head to lake to pick up the rocket launcher. It helped me cross the living quarters gap too.
I use Wineskin to play the game on Mac if you're curious.