We start not with an Amalgam comic, but the book that set the whole thing up:
DC Versus Marvel Comics #1 (1996): "Round One"
Written by Ron Marz, art by Dan Jurgens and Claudio Castellini, and Josef Rubinstein and Paul Neary.
We start with an old hobo with a glowing box, and a young guy whom the old guy has been waiting for. What they have to do with anything, we are not told. Characters begin disappearing from their own universes and re-appearing in the other universe. Spider-Man meets the Joker, Superman meets the Juggernaut, that sort of thing.
Aside: If Superman fought the Juggernaut, who do you think would win? I would go with Superman as far as strength goes, but aren't Juggernaut's powers magically-derived? Would that make him more effective against Superman than he might otherwise be?
Aside the Second: I'd forgotten the insanely ugly costume they had Thor in in those days. Thor should not look as though he's trying to cosplay as Cable.
The Spectre and the Living Tribunal are concerned (or dyspeptic, it's hard to say).
There's a bit with J.Jonah Jameson as the editor of the Planet, which is mildly amusing,.
We end with a big blue guy and a big red guy, who I gather represent the two universes.
Overall: Wow, that wasn't as good as I remembered it being. Once you get beyond the amusement value of seeing characters who don't usually meet encounter one another, there isn't much "there" there. Perhaps it picks up as it goes along.