Okay the wisps are now able to be destroyed but when they die their collider remains. If you shoot with the standard gun at the location where a wisp just was, the shot will explode and will give the "Absorbed" text that normally shows when you hit a wisp.
Also the text for Trivial Exp is displayed as "Trivial KillxpNo XP"
I also noticed that in single player defense mode, when you die, the menu says:
Press <Enter> to retry
Press <Esc> to go back to menu
Escape does not work, to go back you have to hit enter and then Escape to quit the current game.
Last thing and it may not be a bug, it just strikes me as odd. Single Player and Multiplayer are saved differently with level, ship, mods and credits but both share the same bank and weapons. It makes sense to have the same bank so that you can transfer weapons back and forth since they really get no advantage from getting weapons from later areas, but when you have the same weapons on both characters you cannot have two different "builds" on the different characters without having to switch weapons when you switch characters. Just checking if it is supposed to be that way or not.