@efesell: Right, the orbs. I didn't mention those above because I didn't quite have a handle on them yet. I've had the tutorial for them though so I guess I've no excuse. Just another thing I gotta remember using until it becomes second nature.
@imhungry: I've been getting steadily better at Tiger Tiger but it feels like I'd need to play it a lot for all those currency crystals Poppi needs. Like I get a few hundred per complete run and need 6000 for a skill slot or 5000 for an element change? I hope the amount you earn goes up precipitously when you reach the later stages, because I don't see myself dropping hours into that mini-game.
As for big stat boosts it seems like the core chips are the most significant. There was one time I remembered they existed and found that I'd picked up a core that did almost three times more auto-attack damage than the one I had equipped.