In Config/システム設定, (second option from the top) you should have the option to use Full Screen, just click over the geyed out "Full Screen" option. There you can select between Japanese and English language if you need it.

That's the problem, when I click fullscreen, the program flickers, and it goes right back to windowed mode. It's gliched out for me and I was just wondering if it's just me or if other people had this problem and knew how to fix it.

Sounds weird to me...

I'm no expert in this kind of matters, so my only idea is to update your graphic card drivers...