Crack Pairing: Non-shipping example. This trope is used as a gameplay mechanic via Synergy Assists, where each character gets a special attack from activating one particular assist character. The crack part comes from the two characters being from two different shows and having no relation to each other. One of the announcer's lines when a Synergy Assist is activated refers to this effect.
Cartoon Network at one point had Sweepstakes for getting a copy of Super Smash Bros., called the "Smash Hit Giveaway" (Can be seen here). Several years later, they create this game.
The game was released on both the Wii and 3DS. A few years later, Nintendo would do the same thing with Smash 4, though for the Wii U instead of the Wii.
A lot of elements of this game seem to predict elements of Super Smash Bros. for Nintendo 3DS and Wii U. Mac & Bloo's neutral special is the same as Ryu's, the 2nd Foster's stage is reminiscent of the Tomodachi Life stage, both Captain Planet and Blossom's neutral special are similar to Kirby's Ice Breath custom move, etc...
The game was released to rather mixed to negative reviews, due to the flunky gameplay and the various in-game glitches. The reviews to the Updated Re-release seem to be a bit more favorable.
That One Level: God help you if you happen to get the fight against both Bens and Kevin in Arcade Mode...The 3 Vs. 1 level is always difficult, but the Ben 10 one is the hardest.
They Wasted a Perfectly Good Plot: It's not uncommon for people to compare the story mode to that of a fanfic. We have the protagonists of many, manyCartoon Network shows, fighting all of the villains who teamed up, but the villains make some... Rather questionable area decisions (Vilgax in Marzipan City, for one), along with the reveal that the villain of the game is the remote control of the Narrator, which, while done in the manner of many of Cartoon Network's signature comedies, is entirely out of place in aCrisis Crossover, and one could argue that any of the villains in the game could have been better as the Big Bad. Though others find it an appropriate villain considering that the Narrator is implied to be Space Ghost, and his remote would be a fitting thing to link everyone since it was his show that kicked off Cartoon Network's original programming.