After all, it's one of (if not the) most enjoyable and entertaining portable games I've ever played.
Don't get me wrong, its touch-screen-enabled sequel--Rhythm Tengoku Gold, aka Rhythm Heaven/Paradise--is an awesome game, too, but it's nowhere near as accessible as its predecessor, which asks players to do nothing more than press a single button in time to a piece of music.
Thankfully, the graphics and music that circumscribe that seemingly simple action are wonderfully charming and complex. Case in point, the game's first "remix" stage:
(Here's the second remix stage, if the first wasn't enough.)
Sadly, the only way for Westerners to experience Rhythm Tengoku's captivating (and, sometimes, confounding) mixture of complexity and simplicity is to take a trip to Japan--or spend between $40 and $70 on eBay. Still, I think you'll find this title's price of admission more than acceptable if you've played and fallen in love with its sequel.
See also: 'It's show and tell time!' and 'Rhythm Heaven: My favorite DS game of 2009'