So, my OS X Partition got corrupted in some way nobody even knows how.
I was able to rescue my entire Home Folder, and put it on my External HDD, and the Disk Utility in Recovery HD claims there are no problems at all, but it still magically disappeared from my Boot Screen, so I can't use OS X anymore.
In addition, my USB Sticks won't be read by EFI, CDs and DVDs get spit out by the iMac, no matter what, so all I have left, is a broken and glitchy as fuck Windows 8 Developer Preview (yes, this old!).
To come to the point, this Project gets suspended for a while.
Not because I can't work on another Computer, it's because my interest in this Project dropped from 60% to -40%, when this all happened.
Maybe I'll pick up this interest at a later point.
And it's another lesson for me: Never announce something you're working on, until it gets through the Lot Check (if making for Nintendo), no matter how proud you're on it.