To clarify, I am, in fact, a Sony fanboy really. Just to get that out of the way. Also, I will be comparing this to Smash a lot simply because most people know Smash so its an easy comparasion point.

First, mechanics. The controls are tight and responsive. I didn't see any hiccups or wtf just happened calls or anything. However, when everyone is hitting each other rapidly, it would appear that everything slows down. I was concerned, but the others playing with me said they didn't notice anything.

Sounds are good. I like the soundtrack, but its one of those things that either you like or you don't. Sets the mood right though.

Character-wise, there are a fair amount. Not everyone I wanted to made an appearance and there are some questionable choices, but for the most part I was satisfied with the variety present. However, unlike Smash where you can get the general gist of every character, these characters are really different and unique. There are 3 directional attacks per button (excluding X), a block, and a grab. However, beyond the controls, each character's attacks differ greatly. Sly's attacks are one or two combo and the cane doesn't particularly stun or anything. However, Kratos' attacks have large combos with stuns. Colonel Radec has few attacks that can combo, but his sniper shot is devastatingly powerful. Overall, each character takes longer to master than those of Smash, which is questionably good. On a side note, Sly doesn't have any block or dodge, but rather turns invisible. In a chaotic battle, this is incredibly useful. This just shows the diversity in characters.

Now, actual gameplay. As established, kills only come from supers. I agree that the best way to play this would be time, where everyone is just trying to get the kills. It is a much more aggressive style of play than Smash. Simply waiting in a corner will do nothing, but you have to be in the middle of the action. Different characters allow for different styles. Big Daddy is great in close quarters, especially with his ground pound attack. However, Dante is (in my opinion), good for guerilla attacks, not being in the middle but attack those on the outside or fighting one-on-one. Grabbing because incredibly useful, since it actually lowers the opponents "charge" for the super. The supers themselves are a hit-and-miss. Some are great, others...not so much. In general, the first one can get one, maybe two people. This is generally a fair first power-up, since its usually close-quarters and is stoppable. However, we saw massive problems with Sly's first. Well timed, it can get all three other players. Also, its fast and can't be stopped. so its a huge nuisance. But that's the only real problem with supers we saw. The level twos can get up to 3 kills. depending on the character. Level 3, for some, is an auto-3 kill. However, for others, it makes it so attacks kill on spot and actually hitting them is somehow easier, depending on the character. Sackboy will turn them into the bubble things he pops, and Drake will turn characters into zombies from the first game. This can get up to 6 kills (that we saw) but get as low as 0 if you are inexperienced. Skillful players will either stop supers with regular attacks or with their own super. This is a hilarious and fun strategy for the stopper, but annoying for those being stopped. It takes practice though.

The gameplay differs enough from Smash that I find it fun yet not a huge knockoff. The characters are all different. The strategy for winning is different. The maps are fun and dynamic, though get stale. Its still a knock-off, don't get me wrong. But a fun and different one. It fills a different niche. 

It takes a little while to get used to this way of playing. The first several matches I played, I was like "meh, this is ok I guess. Can we play Brawl?" After a while, I was willing to say that it wasn't bad, a good substitute for Brawl. After about 4 hours and playing with the right people, we all had to admit that it was  a really, really fun game. Even the Nintendo fanboy (who refuses to call buttons anything different than A, B, x, and y) admitted it was fun and different from Smash, which, let's be honest, it needs to be. It is not nearly as fun with yourself, but that's the genre.

Overall, the game works great. After a while and after you stop playing it like Smash (and stop comparing it to Smash), it a blast. Just find the character you think you like and roll with it.