[MeechMunchie]

Well, you can use shields to reflect beams back into your face.

Also, real advice: Spam volcanoes. EDDDF[RC] aka Shield-Fire-Fire-Fire-Stone right-click. Spam them everywhere.

Also, the most powerful beam in the game is QFSSAA[LC] or Super Electric Steam Super Beam ("Super" means two of the element). Things pop. Especially pink Space Marines called Aidan.