OMG, that is so wonderful - it turns out MO for the GBA isn't actually a straight conversion with a couple of new bits added, but instead (from what the manual says, at least, many thanks to Nath!) a sort of addendum or missing chapter. Alf did say that the Evenwurst Weiner Factory was built where RuptureFarms once stood, though, which creates some interesting cartography/continuity dilemmas, but nothing too intrusive of Oddworld lore, especially since this is just a portable game.
Break Wind Hill; Fort Glokz.... hehe, cheeky. I think it's safe to say I'm going to look into getting a GBA SP.
