I have to admit, I'm a big fan of Urusei Yatsura, and a bit of a fan of the Ultraman franchise, so when I found this, I was immediately interested.
This doujin, for those who haven't realised it, is a fusion of the classic anime Urusei Yatsura and the classic live action television superhero series Ultra Seven. Ataru Moroboshi is a member of the Ultra Garrison, alongside Mendou, Shinobu and Ryuunosuke, but is also Ultra Seven, a being from the M78 nebula, tasked with defending the Earth from alien invasions and giant monsters with his fabulous powers. In this doujinshi, Ataru and the Ultra Garrison discover an alien plot by Ryoko, Sakura and Cherry to destroy humanity, using giant robot duplicates of the Ultra Garrison, including an Ataru that transforms into an even more gigantic Ultra Seven.
Not only does it work as an affectionate parody of Ultra Seven (for instance, all of the Ultra Garrison seem to know that Ataru is Ultra Seven, and none of them care), but also as a straight up Ultra-style action comic: the battle sequences are very well done, and it manages to mix humour and action very well, meaning that the potential for getting thrown off by a stray joke is reasonably low. The well done art, while simplistic, works well with the battles, managing to get that kinetic feel that the best fighting manga can provide.
While this doujin can only really be recommended to a very small contingent of fans (fans of Ultra Seven and fans of Urusei Yatsura, both extremely small groups in themselves), I heartily recommended reading this doujinshi anyway. Also, there's a bonus strip featuring Ranma as Ultraman Leo right at the beginning...