Its hard to define exactly, but the all of the images don't look polished. It all lacks a certain crispness. The logo has visible jaggies, for example.
You're using a font BebasNeueRegular that doesn't look crisp either. (I see its being loaded with @font-face). Just switching that to Arial (your fallback) in webkit inspector made everything look a lot better.
Simplify your DOCTYPE to just <!DOCTYPE html>.
Your google analytics script needs to be at the footer of the page. Use the asyncronous loading script they provide.
Your background_texture.png and header_texture.png are over 500k combined. Seriously, you need to get these to be no more than 10-20k at most.
Minify your css.
I love jQuery, but you're loading an entire js library to run 10 lines of javascript in global.js. And forget the assumptive argument people make about "oh its on a cdn so its cached in the browser...". Its likely not cached in peoples' browsers. Unless you plan on adding a lot of more functionality to this page, consider re-writing your js to not use any libraries. (Can't believe I'm actually saying that!)
The "GIFT YOUR FRIENDS" and "REWARD TOGETHER" images are cut off at the bottom in Chrome.
Your buttons on the top-right of the page should have "cursor:pointer" in them since they are clickable links. Further, they are links so you should look into your css and see why the default pointer behavior is being overridden to begin with.
Sorry that this is just a list of technical things I'm laying out. I'll leave the "does this color scheme make me feel warm and fuzzy" stuff to people who have more of an eye for that.