This issue is part one of a two part limited series, that's part of a broader IDW wide crossover. With only two issues the story can't be that deep, but then what would you expect from a series that is "Transformers vs Zombies".
The basic plot of this issue is that Galvatron's ship crash lands in Las Vegas and a stream of human zombies and robot (and maybe Transformer?) zombies emerge with Galvatron and his seekers right behind blasting them away. Galvatron seems a bit more like crazy UK comic Galvatron than the previous IDW incarnation.
The Autobots arrive with unremarked upon but incredible speed to the crash site with a couple of Spike's troops in robot fighting suits. The suits don't however prove enough protection from the zombie robots. The Autobots erect a forcefield and subduing Galvatron long enough to get an explanation of what's going on.
Roche's art here is good quality but his Transformers are more cartoony than ever. I like it but it wont be to everyone's taste.
For a book about zombies there's very little of them to be seen. The robot zombies are odd and it looks like one (or more) of the Sweeps is a zombie too but it's not really made clear. How these undead differ from the Dead Universe, and what these zombie robots are also needs more explanation, but that's for part two I guess.
It's also odd to me to see a zombie story where characters know what zombies are, with reference given to the directors of Zombie films. The generally convention of a zombie story is that zombies have never existed before in the fiction (or reality) of the world which allows the zombie apocalypse to occur.
Continuity wise, the Autobots are led by Bumblebee but accompanied by Optimus Prime. The dialogue, that makes it clear that Bumblebee is in command, may have been a later editorial correction. Other than that there's no real clue as to where it fits with the ongoing series.
There is however a major status quo change for one of the characters. Spoilers with Kup loosing his cy-gar and remembering the events of his spotlight. It's a good fit for the story though but seems more important a plot development than I would expect in this series.