PS - Tiny Giant inspired lettering in the pic.
heh, thats cool with me.
Anyway, it's looking great, I wont comment on the pixels cuz I think they work well. My immediate reaction is that drop shadow is gonna be a nightmare to line up over a tiled background in HTML, I did something similar on when I built the website of the company I work for and as you can see I didnt bother with a background tile...
http://www.kgk-group.co.uk/Another thing to think about is are the pages going to scale? so if you have more content the page gets longer, if so your gonna have to do something with the earth tiles to the side, cuz they might not work as the pages increased in length depending on your content.
As for a playable top, sounds like a nightmare, your basically having to do a game just for the top of your website and it'll have to be done in flash so theres all sorts of layout problems unless you do the whole thing in flash, I'd just stick with a few animations at the top, you could easily make it look like a platform game was going on just using animated gifs. Remember people are coming to your website to look at your work not to wait for a platform game to load that they never wanted to play in the 1st place, as nice an idea it may be.