Good luck! I'll tell you now though, it's only gonna get harder from here on out. Make sure you power up often!
I beat Elvis, and then beat him again, so I'm partway through the 3rd stage right now.
Once I figured out how to recharge the TP gauge quickly, it's been much easier. I think the toughest bit I ran into was the 3 mini-bosses in a row.
The more I play it, the more I like it through. You just keep unlocking better, and more over the top moves.
It reminds me a bit of No More Heroes as well, when it comes to the cut-scenes and level progression.