Above all,
Trinity Universe has fun with itself. It's an incredibly light-hearted approach to both design and story that, based on my first few play hours, is proving enjoyable. It has the same approach as the first
Disgaea. There are jokes about videogames (mainly JRPG conventions) at every turn and a few references I'm pretty sure I'm missing.
The entire concept is woven around a giant floating asteroid/ planet, the Netheruniverse. The area has an odd magnetic pull causing everything - from buildings to small planets - to enter its orbit. The influx of orbiting garbage doesn't phase anyone, though when it begins to fall out of orbit and into town... well, there's an issue.
At the start of the game, you can choose between two characters, the Demon Dog King, Kanata, and Valkyrie Rizelea. Each character follows their own story revolving around what to do with the gobbledygook periodically falling from orbit and crushing people's houses. Rizelea wants to end the destruction by convincing Kanata to take up his true position as Demon God Gem (just roll with me here, folks). Kanata isn't high on the idea, and would rather find a solution that doesn't involve him turning into a rock. Barring that, at least he'll get a great adventure out of the deal.
I had a lot of fun with Trinity Universe's ability to have fun with itself and its story, but it becomes a victim of its own playfulness. Jokes are great; the sillier the better. But whenever the game tries to take a step back and examine some larger plot issue (Kanata questioning why Rizelea wants to save the Netheruniverse, even though its not her job), it's hard to take the game seriously.
Trinity Universe is a bit different from typical RPGs. Though a great deal of gameplay takes place in dungeons, most of the overworld consists of navigating through menus. This cuts down on time spent wandering around searching for shops and other items, though at the same time it keeps the Netheruniverse from becoming anything more than a few still images. I liked the ability to quickly jump from store to quest, but a sense of what I was trying to save would have been a welcome addition as well.
Visiting dungeons is a fun and rewarding experience. Since trash floats in and out of orbit, every time you visit a dungeon, new items are churned up. Dungeons will eventually drift out of orbit. If you're in one when this happens, it's a mad dash through the door to escape. Of course, this is also when the really valuable items begin to show up.