ok...I know this has been said before...but contrast! Everything seems to get lost in the background:
Also, I played around with the HUD...Personally I think it would be better to have things line up, it just looks a bit more coherent that way, and it's a bit easier to look at. I got rid of the curly part, as it seemed a bit unneccecary. Also, it would get annoying to read once you got down to low health...and you're more likely to be checking up on your health when you're running low. I seperated the level and the exp needed, this way it's a bit easier to read. Before you mentioned that the "/602" was supposed to be your exp, I thought it was some kind of decoration...
The right bar - I made it less swooshy, if it's just a straight line, then it's easier to see exactly where the bar is up to, otherwise it's a bit ambiguous. Also I switched the way that the bar reads. I think it's nice to be consistent, this way both bars face the same way and it means you don't have to jump from reading left to right to reading right to left. Also I closed the bar off so you can tell exactly where the end of the bar is.