pro
More than anything All-Stars is a ton of fun to play. The fights are frantic, colorful and unpredictable. Dynamic levels with up to 4 players mixing it up with all their moves makes every match seem new and fresh. The default option of having the score turned off is absolutely recommended as it will keep everyone fighting until the bitter end. When someone is tied at the end, the game kicks into overtime which further increases the tension.
pro
The 20 initial fighters provides a nice mix of personalities. Not many can be called pivotal to the brand, but most are nonetheless interesting in some ways. SuperBot did an amazing job not only getting a lot of the original voice actors, but also making sure that key moves and references from their games of origin translates into their fighting style. If your favorite character is in the game you can rest assured that he or she will most likely play the way you remember that person. While the supers are a bit hit and miss, some of them are really cool.
pro
All levels are mash-ups between two games, and most are fun. Having the level being built LBP-style while you fight around it is cool, and when that's done it turns into a round of Buzz. It's quirky, but it's entertaining. Hades smashes up the level before getting attacked by Patapon. It's clear that there's a lot of love put into the game both with characters and levels. I'm eagerly awaiting upcoming DLC like Kat from Gravity Rush and Emmet from Starhawk, and hopefully a lot more.
pro
While there is a campaign, the multiplayer is of course the bread and butter of All-Stars. It works as you would expect with ranked and unranked matches. You can play free for all and 2 vs 2. The single player stuff includes a short story mode, battle trials, practice and combo training. By beating story mode you will unlock icons and backgrounds that mostly comes into place when you win matches online.
con
There isn't really any depth to the combat. While this makes the game hugely accessible, I think a lot of the more hardcore fighter fans will check out the various supers and find themselves done with the game.
con
The presentation comes off as very cheap and the quality of the product doesn't really show until you're in a match. Sure, it's not critical by any means, but the overall impression is a bit lacking.
con
Between the intro and the outro the single player campaign is pointless. You can finish the game with a character in about 15-20 minutes, and the final boss is a disappointment. This might be fine for fans of easy trophies, but a more robust and interesting campaign would be neat.