It's an experiential thing, rather than actively a game. As the instructions sweetly put it, you win by "pressing not escape". This is along with the warning, "don't get seizures or thow up, it's just a hangover."
I haven't had a hangover since Jan 1st 2000, so unlike the rest of RPS I'm not that qualified to judge the realism. Well, if they ever stopped drinking for long enough to reach the point of hangover. In fact, mine might be more recent than theirs based on this logic. Anyway, if I remember rightly, hangovers suck. This experimental game certainly creates the sense of being trapped inside a head made of steel bars, along which some bastard keeps rattling a metal stick.