Portal 2 features new gels that do all sorts of interesting stuff, but there’s no gel that will let you walk around on the walls. That’s because it didn’t turn out so well, although anybody who’s ever played the original Aliens vs Predator could probably have told Valve that.
“At one point we had a new Gel that allowed players to walk up the side of walls. While this added a new twist to the game, the effect was so disorientating that it made people nauseas [sic],” Portal 2 writer Erik Wolpaw says in a recent interview published over on EA.com.
“While working on a first-person game you always have to be aware of that issue so we removed that Gel. We also made changes to frame rate and movement that will help anyone play Portal 2 even if they do experience a feeling of nauseas [sic] while playing other first-person games.”
