I'm currently stuck trying to get the last rock piece, and for some reason can't get to the last silver door.

The reason for this is, its behind a blue door, which I can't seem to find the key too. I've searched the room repeatedly and still can't find it. I've opened the door before I had the silver key so I know it exists but I still can't find it again.

I swear it used to be right here, but if that is where it is supposed to be, maybe I caused a glitch that makes it not show up anymore

This glitch has happened to me randomly on very few locations and I can't find the reason so far. Try to reenter the area a couple of times, the blue door should be open after a few tries. Could you send me your save game so I can take a look at the data? That would be helpful.

I will take a look into this bug and release a patch in the near future.
Thanks for reporting

I'm having this exact problem, too. I can't find the blue keycard leading to the fifth silver door (in the ice level) no matter where I look. I've uploaded my save here.

Edit: or not because for some reason it refuses to accept the file.

I have this problem too.

I tried exit and re-entering the door several times, didn't help.

Tried the patch, didn't help.

I sent you my save data at The Daily Click, Blue66. Since it got server overload earlier I couldn't tell my problem here so I wrote there first.

Thanks.