Thanks 
sved, I've just uploaded a version with arrow key controls!
if you clear your cache before loading (on chrome press f12 to enter console then right click on refresh and click empty cache and hard reload) it'll make sure you're playing the latest version :D
Anyway, I'm still working on the "randomness" factor which determines platforms, enemies, item spawns and chest drops, I think I'll tear it out and re do it in the next update so I can have a bit more control over it.
Essentially at the moment I have a pool of numbers that are randomly drawn as the player descends, these determine what platform/item/enemy is going to appear next, with lower numbers spawning "easy" platforms. as the player gets deeper i'm just enlarging the pool of numbers to include more elements. I think what I need to do is form "groups" that will let me tailor specific areas i.e. create an area that will have heaps of mushrooms and very few platforms to make a kind of "bouncing" zone, or an area that has lots of skeletons or something!
that way I can just sort of randomly assign a "zone" which will then in turn randomly assign these selected elements inside it so it's still dynamic and not too repetitive, but at least retains some kind of structure!
as always, thanks for playing :D