I have one myself actually, and it took me a while to figure out how to open it too... lol. Here's what you have to do though.
At the left side where the blade stick out of the case there's a lip at the top with 3 bumps near it. Just pull up on this edge and the case should open.
Also on the lid there is a piece at the back the can slide towards the back to reveal the instruction manual.
And finally the dwore on the front at the bottom can be a pain sometimes but you have to pull it out for this is where the cord for the controller lies.
If there's anything else just let me know
P.S.
I edited that pic really quickly, and yes I know there's spelling errors. But you get the point. ^^;
Jam it back in, in the dark.