I recently bought the Humble Bundle #4 and I've been having some odd problems.
It lags at the same points in 2-5 (The Big Empty), and doesn't lag pretty much anywhere else.
Bandage-unlockable characters are not unlocking.
Some text is cut off, only leaving the first letter of it.

I'm using Debian on proprietary Nvidia (generic) drivers, x86 version.

Graphical glitches:
Letters being cut off:
http://i.imgur.com/7VnoR.png
Not sure if it's not getting data or something else in custom levels:
http://i.imgur.com/fnK6v.png
Flashes between these two shots, and another with an X replacing all characters that shouldn't be unlocked yet that I couldn't get (note: 22 bandages):
http://i.imgur.com/ntKJR.png
http://i.imgur.com/a6VEY.png


EDIT: I'm not sure if I should put this here or file a bug report. I don't know if it's my end or not either, so I guess this couldn't hurt.

The controls have to be edited in a config file in the directory it was installed in. The file's name is "buttonmap.cfg" and how to edit it should be self-explanatory once you open it in notepad or the like.