1.) in skulltag (doom multiplayer port) it will let you play: singleplayer (normal doom iwad levels) singleplayer deathmatch (with bots and ai) and of corse, multiplayer. it would be cool to be able to play more classes with more weapons on singleplayer when unable to connect to the internet. will this happen?

KA has single player the way UT or Q3A does, i.e. you don't need more than one computer and no human players to be able to play all game modes and all maps included.

wonderful! can i change my classe during the game too?

Yes, but new class will be applied only after your next respawn.

Thanks!