I love playing Super Smash Bros a lot, so... I think it's completely different. In Demigod, you use skills completely in another way than in SSB (super smash bros) - wii controlers, etc vs mouse + keyboard. Also in demigod you need to think strategies of what you are going to do in future, etc, while in SSB you just fight fight and fight. Yeah there are special moves, powerful weapons, but besides that you just mash buttons (yeah with some combos, but is that strategy?).
So overall it's far from real fighting game and is closer to strategies (DotA like games where burrowed from a real strategy game Warcraft). Imagine if in Starcraft or other strategy game you could control only one unit and it could level up, get skills, etc. It would be pretty much DotA like, except it needs a good map, neutral enemies, etc.
