I picked this up on Steam a few days ago and have become slightly obsessed with it. as in, I am hearing the music in my dreams at times, and find myself humming it as I go about my day.
it's a lovely, quite melancholy trip into the abyss, in which a hapless fellow bounces about, shooting stars and trying not to run out of probability.
I'll explain that last, later.
there are three game modes --
in Beginner, the object is to scatter as many foes as possible. in short, kill them without mercy.
in Expert, it's depth that matters -- delve as deeply as possible before your chances run out.
oh, and you should probably still kill things, so you can level up... but the depth's the real thing here.
I'll get to the third mode in a moment, because a bit of explanation must come first.
when you destroy enemies in either Beginner or Expert, an experience orb appears.
sometimes it's JUST experience. sometimes it comes with 3 or 6 shots of your star.
sometimes there's a little heart inside, which does just what one would expect -- it boosts longevity a bit.
getting enough experience grants a level-up, which appears as a brightly-flashing line across the playfield. crossing the line lets the character gain a new ability (or improve an existing one),
as well as cancelling any fall and healing the same as though one had picked up a heart.)
in this game, the health meter is insane.
there's a rapidly-changing set of phrases and numbers in top-center, all expressing probability of some desired outcome.
when a run begins, these numbers are in the 5-6 digit range mostly, but as your fellow takes damage, the numbers dwindle -- when you see 1-3 digits and hear the warning siren coming into the music, it's time to be super careful.
that same siren also sounds, much more loudly, whenever a particularly dangerous enemy boss shows up.
eventually, luck runs out, and one's left staring at a big fat 0 under some statement of what could have been... but won't be, no matter how much you play.
death is inevitable here, but it can be really fun getting there.
finally, I'll mention the third mode -- Karma -- which is what makes P0 even more awesome.
playing Beginner and Expert runs gives Karma credit.
Karma maxes out as 10 ("X", in game terms). when playing a Karma run, you get to select as many abilities as the number of Karma levels allows, and go through an even-harder-than-expert run to prove your mettle. (you also lose 1 level of Karma each time you do a Karma run, but it's not terribly hard to regain the level by playing Beginner/Expert a few times.)
in this mode, collecting the orbs enemies leave after death is the object -- which makes it the most difficult thing, especially since Karma mode teems with enemies who can easily get in the way of scoring the spoils of recent kills.
in short, it's very replayable and lots of fun. my only real regret is that it doesn't have more variety of music, but that's not such a big deal, as the music that it DOES have totally fits the action.