Space Jump about halfway down, just enough to get their attention, then back up. Crouch on the edge of the platform, and fire diagonally downwards at the pirate as it climbs up. He'll stay on the wall, shooting away from you, until he dies. Wait for the next one to come up (it'll take about two seconds), then repeat the process. They'll go down FAST.
I know he was going for a low precent game but is it possible to only have the ice beam at the very end? what about the suit you get it gives you the best beam
The ceiling isn't what's destroyable, the ceiling is automatically able to be jumped through, it just doesn't look any different from the normal ceiling. It's above the block that can be destroyed in that room, and if you destroy the block its hard to get up in there and you need to wall jump to get up. It's easiest to stand on the block and just jump up.