Guess who's the only itch.io-bound maniac butchering Dawn Chorus' gamefiles.
Okay, the variable is called "nhia_beer" and it's only semi-important in Torulf's route. All other changes are small and happen during the fireplace party, here's a full list:
(spoiler)
During the fireplace party, changes numerous inconsequential lines like whether or not Lake gives Arvo another bottle, and who chugs soda during "Never Have I Ever".
During "Spin the bottle", if you are on Rune's, Bjorn's, or Torulf's route, sober Arvo can ask "What makes you happy?", while drunk Arvo can instead ask "What do you think of me?".
During "Spin the bottle", on Rune's route, when Lake dares Rune to kiss Arvo, sober Arvo tries to protest. Drunk Arvo decides he is "in no state to protest" and is pretty much anticipating it.
During "Never Have I Ever", if NSFW is enabled, drunk Arvo can wreak havoc at the table by saying he never thought about drinking his own piss. Chaos ensues when he scores some points.
In Torulf's route:
During "Spin the bottle", if they haven't slept on day 1, drunk Arvo asks why Torulf has been avoiding him. Sober Arvo gets normal questions.
Changes what Arvo asks Torulf after the fireplace party, if they haven't slept on day 1 - drunk Arvo once again asks why Torulf has been avoiding him, and sober asks what's between Torulf and Lake.