Well I'd still say a 1 on 1 is tougher in almost every way to create. Whilst you may technically need more backgrounds, you still need to make considerable scrolling backgrounds in 1 and 1 beat-em-ups. You need less gfx for a scrolling one, especially for each character, on a 1 on 1 you need loads to make a decent arsenal of moves. Then you've got to implement AI, much harder on 1 and 1 and then do all those complex fireball style directional spins.
I'd say scrolling beat-em-ups are more fun too cos you can play coop :)
I'd say scrolling beat-em-ups are more fun too cos you can play coop :)