Uh, there's a DDR time unlock system trick for 10. Turn off everything in the options.

Oosanbashi and Contemporary Nation 2 are what make 12 great. The problem is, 12 is lacking Elegy. It might be an unlockable, but I'm doubting it. I'm really enjoying the unlock system and theme in 12, it's just peaceful. 11's airport theme felt rather isolated.

Pop'n 10 is what I learned Pop'n on in the first place, but 12 feels better somehow. Of course you're not going to get Seisyun Punk, one of my favorite songs in the entire Pop'n series, but there's more than enough to make up for it.