Here come some negative comments- I hope you don't mind.
I hate to tell you this, but, like binkyboy said, this style isn't "completely original". That's fine, though, and so long as you're trying, your style will become more of your own, and will develop. There isn't any such thing as an "original" style; I've been trying for years to make my style distinct, and it still gets compared to Tim Burton, for instance. The style of this piece in particular reminds me a little bit of the anime Lucky * Star.
I have some little critiques to drop on it. The first thing that popped out to me was the strange look of the feet, especially those of the girl, which have a potato-like shape. The hands are somewhat odd in appearance as well. The girl's breasts are lumpy looking and a little uneven, and a valuable lesson you should learn should you be drawing well-endowed women is that breasts will never look good unless they're smooth, round, and symmetric (that applies to all sizes, but the larger the breasts, the more they're noticeable). The legs just have a strange thickness to them and look blocky. For the characters in general, I'd suggest you study and practice with anatomy. Even in cartoon styles, anatomy is a very valuable concept to understand, and you could benefit greatly from working with it.
The next thing that pops out about the piece is the strange appearance of the portal thingy behind the characters. It looks like you took some doodled lines and filtered raped them, and that causes it to look out-of-sync and ill-fitted with the rest of the style. An effect should be consistent with the rest of the piece, and here I think it would have been a good idea had you drawn an equally cartoony-looking wormhole behind the characters. Photoshop effects generally do not look good unless in the hands of an expert.
While the main subjects of the piece are quite flawed, I have to admit that I like what's going on around them. The perspective is a little wonky, sure, but I like colors and aesthetic of the background- some people don't pull off simplistic backgrounds well (myself included), but I think you've done a decent job with that here.
I hope some of this stuff helps. Keep practicing and you'll improve, and maybe you'll develop a more personalized and original style along the way. The best way to go about that is to stop trying to draw a specific way and draw in the manner that feels the most natural to you. Good luck and keep working at it!