The main idea for the game should get a perfect score. However, the realization of any CN fan is far from achieved in this game.
Graphics: One of the first 3DS games, the graphics may look a bit unpolished sometimes, like something was lost in the transition from 2D cartoons to 3D characters. The movies could use more work too, like having actual animation instead of still 2D characters moving in a paper-like scenario, which somehow doesn't fit with the game's melee style. The 3D effect could've been exploited here as in every other aspect of the game. PTEs are the only thing in the game worth of playing in 3D.
Plot/Story: Well, nothing original here. Characters facing off through different cartoon dimensions can't be that different from other crossovers. Some were more fun than others, and the ending was sort of unexpected.
Sound: Well, here's something that didn't come out right at all. Music was not as memorable as I would've expected. There were a couple of tunes I enjoyed but not all of them. SFX was OK but the character's voice over bits were horrible. If you don't want to do the whole track ala Zelda rumblings I understand, but there were some catch phrases thrown in there just for the sake of it. Sometimes, they didn't even make sense. This was a major fail.
Gameplay: If you're looking for SSB look alike, you got it here. Things are pretty random even when you think you've mastered a character; yet, that's what we like about these games. However, some stuff felt a bit unbalanced. Not only the character but the way the percentage thing works: it's much more harder to throw your enemies out of the fray than it looks. Multi-player suffers the same feeling. The special parts in the story mode could be more interesting but give a nice touch. The grab button is a bit buggy sometimes, which is a shame given the items and assists are really good. I like the way PTEs were carried out, is more entertaining than the Super Smash mechanic.
When you look at various rating sites, you will always find a large amount of negative reviews on this game. I rented it because it look interesting and there are very few good 3DS games out right now. When you start out in story you will see there are various worlds and many characters with their own fighting style. The story is nothing new but can still hold your interests through to the end. The levels feature basic side scrolling from beginning to end with enemies and obstacles you need to go through. The controls work well enough for the platforming and even the fighting (which most people hate) works pretty well, though there were times I died because the controls were not responsive enough. Going through the story is a little repetitive, though the settings do change enough to make it a small treat to wonder through your favorite character`s worlds. The only major problem I find with the game is its boss fights. While some work(like the final boss) some also are very difficult because they either trap with with overpowered moves or can just blow you away without warning. With story completed its time for the Battle mode. This is your basic 1 vs 1 all the way to 1 vs 3. The game sticks with the Easy-Medium-Hard setup. Unlocking characters in this mode is a bit harder than through story(those unlocked in story are not unlocked in Battle). You need to win X amount of game in order to unlock all characters. In battle mode you also have Local play and Download play. I love the download play option allows for 4 people to battle with only one cartridge. The only downer is there is only 4 characters to use and you cannot unlock more(battles won go towards unlocks in regular mode) Those characters are Ben Ten, Dexter, Buttercup, and one other i cannot remember... Overall the game is very solid and worth it if you have friends with 3DS`s or just need a good game while you wait for Smash Bros to come out(it was announced for 3DS & Wii U)