Batman and Superman's trip to Kingdom Come's Earth-22 gets off to a rocky start

gamesradar.com:

It was announced a few weeks that DC Comics and Mark Waid would be returning to the universe of the groundbreaking Elseworlds series Kingdom Come in the pages of Batman/Superman: World's Finest. That arc started this week with #20 and, indeed, it wastes no time in getting Bruce Wayne and Clark Kent across the dimensional void with a little help from The Flash and his modified Cosmic Treadmill.

The reason they're so keen to travel to Earth-22 is that Superman's protege, Boy Thunder, is missing. Back in World's Finest #10, the young hero (real name David Sikela) took on the Joker and attempted to kill him. This prompted Superman to try and strip Boy Thunder of his powers in the following issue. Before that could happen, however, the young hero was accidentally sent reeling across the multiverse, ending up on an unknown parallel Earth.

Flash finds young David at the start of the new issue, but as he says to Batman and Superman, "News that's good, news that's bad." When the two heroes make it over to Earth-22, they discover that almost all of the planet's heroes have died.

What's kinda interesting about the issue is that, while we spend a lot of time in Kingdom Come-land, we don't actually see that much of it. A significant chunk of the issue takes place in Booster Gold's superhero-themed Planet Krypton restaurant, where Bruce and Clark orient themselves and plan their next moves. 

There's a few good gags here (Booster Gold selling a dish known as "the Creped Crusader" for one), but the most affecting part is Bruce not incorrectly pointing out to Clark that he will likely have a hard time if he tries to legally adopt David when they get home, pointing out that he only managed it with Dick Grayson because he is rich and can