I actually call the skins achievements myself ;) They function exactly the same. Steam requires a ton of graphics for the store and achievements :( Otherwise it would be fun.
Side note: at least one of your main followers won't use Steam even if his cybergaminglife depended on it.
I would be extatic if you released a (sometime updated) browser/Linux DLdable version of the game before you join the Steam cohorts.
(just resetted around arena 6450 because me purging cookies unsafely, will reset again this weekend to taste the 'new beginning')