So there is a demo for Project X Zone on the 3DS eShop & I gave it a whirl.
I'll say it's good casual fun, for both good and bad. Not only are there solo support characters to call in, if you position well you can bring in another duo on your attack and rack up the damage as the numbers fly everywhere. That's kind of cool. The downside is that based on the demo there isn't depth here, it's thoroughly a button masher. Such mashing has not occurred on my 3DS since Code of Princess (which I recommend, it's a good and goofy brawler). There's maybe a little strategy in that as you do battle you build up these points that you can use to counter an enemy attack or reduce damage from an attack, or just stock up for uber special attacks. But as near as I can tell the extent of strategy is really "don't divide your forces, and you'll do just fine." Super Robot War OG took more thought.
The allure of the crossover novelty is the main draw here for sure. The good news is, I steamrolled the demo three times just today and I wasn't finding myself sick of it. Good guys, bad guys and explosions, as far as the eye can see, etc etc. It's fun, I could see myself buying it despite the apparently basic gameplay.
Naturally our opponents are ugly monsters and demons. I'm surprised they didn't just go all in and include some Nazis or Nazi stand-ins. Then again, I've only played the demo!
I would suggest that it's not the medium, but the quality of perception and expression, that determines the significance of art. But what would a cartoonist know? -Bill Watterson