Bit.Trip Runner is profoundly difficult, as anyone who has played a previous Bit.Trip game would guess. It's probably one of the hardest games I've ever played, and in a way that most developers don't dare to make their games. Basically, if you already have high blood pressure or a short fuse, you should stay far away from Bit.Trip Runner. And if you don't, you should wear the Wii wrist strap while playing. Not because it uses motion controls, but because you'll occasionally get the impulse to throw something.
If that doesn't scare you off -- if you welcome the challenge, or are a patient person in general, perhaps with access to the occasional cup of soothing tea -- then you'd do well to try out Gaijin Games' rhythmic, nostalgic version of the side-scrolling platformer.
Bit.Trip Runner is an "auto-running" platformer, like Canabalt or Tomena Sanner. Commander Video constantly runs forward of his own volition, and it's your job to make him jump, slide, kick, and block such that his progress isn't impeded. The obstacles are placed such that your movements correspond to sounds in the game's chiptune soundtrack. It's a rhythm game, but rhythm is just something that happens naturally as a result of gameplay, not the basis for gameplay itself. It's like Rez as a platformer.
The levels through which Commander Video runs are filled with surreal imagery, like giant faces watching you slide underneath them, and mine carts running back and forth under pipes producing "beats" (the square dots in Bit.Trip Beat), all rendered in a style that fuses Atari-era chunky pixels and modern polygons. The Atari nostalgia is taken even further, with Pitfall-inspired bonus levels and a trailing rainbow behind Commander Video that looks like a Breakout level. It's much less abstract than the kind of pulsating psychedelia presented in previous games. The imagery gets a bit less fantastic and more repetitive as the game goes on (there are three distinct "worlds" with multiple levels in them), but it's always lively.
As for that difficulty. Bit.Trip Runner tolerates absolutely no mistakes from the player, demanding memorization of each level. You can miss item pickups (gold bars for points, and bandages that add a level of complexity to the music and increment the score modifier) but if you collide with one enemy, miss one jump, or touch one wall, you are immediately zipped to the beginning of the level. Even the other notoriously difficult Bit.Trip games let you make multiple mistakes before having to start over.
Despite being, empirically, less forgiving than its predecessors, I find Runner less frustrating. The levels are all much shorter than the 15-minute ordeals to which previous games subject you, meaning that you've lost much less progress when you restart. Restarting is also instantaneous -- no game over screen, no save menu, just a few toe-taps.
The result of these super-brief levels is that the pain of failure is much less intense, and you get to experience the euphoric high of completing a punishing Bit.Trip level several times in a normal play session. When I fail in Bit.Trip Beat's second boss fight, I don't even want to think about trying again for at least a week. When I fail in a Runner level, I keep trying until I finish it. Unfortunately, the boss levels, and those immediately preceding the bosses, are a bit longer than the normal levels, and they hurt.
I suspect the brutal difficulty in Bit.Trip Runner will be polarizing -- some will find the challenge exciting, and some will find it too stressful. My personal experience occupies something of a "sweet spot" in the middle: when I'm playing, I alternate between boiling rage and relief, but it averages out to a general feeling of satisfaction when I take a break.
This review is based on a retail build of the WiiWare version of Bit.Trip Runner provided by Aksys.