"Bogus Journey" unfortunately lives up to its name, with a sequel that captures very little of the charm of the original movie. While you can't accuse director Peter Hewitt of playing it safe - this is an altogether darker and weirder sequel, with Bill & Ted spending most of the film exploring an unpleasant afterlife - I don't think he understood that a great deal of these characters' appeal lies in their innocence.
Evil robot themses are trying to turn what remains of Bill and Ted's lives bogus, so they have to travel all through the afterlife to find the genius(s, or genius, it's a bit confusing) to bring the world back to its excellence. And it all culminates at a battle of the bands, the only appropriate place for such a bogus journey to end.
I actually prefer this sequel to Excellent Adventure. It's darker (the nightmare/hell sequences actually bothered me as a kid) and I loved the references to Star Trek: TOS and The Seventh Seal (although I would only understand this one as an adult). Looking forward to the very recently confirmed and long-awaited upcoming completion of the Bill & Ted trilogy!