I've played through most of the game in normal mode before hardcore mode came out. Wanting to get the achievements, I immediately started a new hardcore game. First off, every few seconds, my framerate drops so low that I have to take my hands off the keyboard and wait for things to go back to normal. But back to the main point; at Bush Rescue HQ, where there are a bunch of invisible boxes above the water, I noticed an extra box that I couldn't break. All my rangs would just go right through it. Thinking it was a one-time bug, I re-visited my old game. It started out normal, but after a few seconds the extra box would appear out of nowhere. I loaded both saves repeatedly, and every time, the same thing happened. It gets weirder though. After a few reloads, the normal (breakable) invisible boxes took on a missaligned version of the texture of the exploding boxes when viewed with the infra- and x-rangs, except for the extra box, which looks just fine. Besides that, they behaved normally. I continued reloading both saves, and the boxes still had the wrong texture. I can only assume my game is cursed somehow.