The Basics: Members of a scientific expedition are being mysteriously murdered.
The Story: I like the story in this one. It's definitely different. It actually has a more Ultra Q/X-files feel to it than most episodes and that's a good thing. Only thing that drags it down is the obligatory "grow to giant size" sequence at the end.
The Kaiju: Greenmons is really a mixed bag, though more in execution than concept. For one...a hundred demerits for the uninspired name...basically a shortened version of "Green Monster". LAAAAAME! I like its motivation in going after the members of the island expedition, but they throw that out the window when he kaiju sizes. The creature is a little too anthropomorphic for my tastes, especially a scene where he bows to Arashi...basically saying..."take your best shot". The creature did have some interesting abilities though, but overall...not a fav.
The Acting: Big bonus points here for Akihito Hirata's first appearance as Dr. Iwamoto(sp?) and special guest star Akiko Wakabayashi as the expedition photographer.
The SPFX: Average. Greenmons too often looks like a guy wearing a blanket, but that's my biggest complaint.
The Other Stuff: Very little explanation is given for the monster...even compared to most japanese critters. Ultraman reacts to Greenmons poison mist even though it is HIGHLY unlikely he could be harmed by this(given that he flies through space without breathing and so forth). Two possibilities...one...Ultraman and his kind were once organic beings..and he's reacting based on instinct.....or the Hayata persona is reacting subconsciously. Either way. Ultraman is never truly threatened by Greenmons and he defeats him easily.