Spiderhead: and the webstone will be a while until out (over an month) and yes Fishhead will be in the credits.
Here is what is included (maybe changed)
*20 levels
*Final boss
*minigame
*Secrets at end
*choice of 4 weapons: pistol, shotgun, machine gun and flamethrower
*5-8 bad guys
*new charaters: Spiderhead and Snowhead
*original charaters: Fishhead and Highair
and more!
i get more screenshots when preview is out