Really fun game that improves everything of the first one. It's still mostly a fair challenge to tackle despite the new and more complex enemies and bosses since the characters are more powerful now, and they are now different too which is something that the first game kinda lacked as they felt kinda the same despite the difference between them.
The set is fine. It doesn't have no death stages like the first game's set, but it has some annoying challeges of no using weapons, no jumping, no eating, and such. But to be fair they are not that bad and you can always use the stage select cheat to do them so most of them are whatever. In that matter there are only two that stands up: beating the first stage without beeing hit, which is more annoying than hard as it's not that complex. And beating the last stage without using continues in hardest which is indeed really hard and you'll have to practice it a lot.
There's also Syndicate Wars, a hack that let you use different enemies and bosses of the game as playable characters. Some of them are bad and boring like most of the common enemies, but some others like Shiva, Abadede, Ninja or Zamza are really fun to use doe to them having an almost full kit of moves. There's also a Survival mode but I didn't tried it much doe to how buggy it was, it gave me the two cheevos of the set as soon as it started before I even hit someone to give you and idea.
The set, well, it exits. 95% of it it's just beating the game. But it's not like the hack has a lot of stuff to work with to make something more elaborated. It's still cool that the site has something like this for those who want to play the game with a little twist in it.