One undeniable improvement is a larger roster: There are now 20 monsters lining up to stomp the cities of the world into rubble. But frankly, the two new guys don’t add much. Battra is basically a goth-y reskinning of Mothra (though, to be honest, that's faithful to the source material), and giant lava gremlin Obsidius - a developer-created stone monster - doesn't fit in very well and isn't likely to be popular with Godzilla die-hards (the only people likely to forgive the gameplay). Oh, and only three daikaiju are available at the start of story mode, so you have to beat story mode about 15 times to get everybody unlocked.
There are only two play modes, and both vary too little from what came before. One is the self-explanatory brawl mode, in which two to four monsters duke it out. Story mode thankfully discards the half-baked side missions from the last game, but has you limping through "missions" that are just brawls that occasionally have crystals to smash instead of monsters. Theoretically, each monster belongs to one of four "teams" - meaning, if you encounter two other monsters in a level, attacking one will usually convince the other to team up with you. But it doesn't add much life to the party. There's also another new kind of power-up in the form of power surges that make you faster, tougher, more energized, and so on, but they seem to add to the slowdown, so we don't recommend them.
Quality is lacking everywhere. Cutscenes are narrated slideshows that actually reuse the same panels multiple times. There's apparently a whole elemental damage system as well, with each attack having qualities like blunt, edged, electric, or radioactive - but it's never explained, even in the manual. Godzilla's basic throw is broken and just dumps the enemy at his feet - not some minor monster's throw, but Godzilla's. The owner's manual lists the wrong button command to use a power surge. And there's no online play at all...