Overall I am balanced perfectly between "that was cool" and "what crack were you on?" Since the balance maintains over multiple watchings, I have to call myself overall content.
This is clearly meant to be a precursor to the Ultra Galaxy movie, though I say that as much because of the packaging and the timing of the release as I do from anything that happens in the episode. There is this last scene, though.... As such, it has to be set, at a minimum, at least 50 years after Mebius. (This is based on a comment in the first episode of the first Ultra Galaxy series about there being no monsters on Earth for over 50 years.) It's probably a lot more years, given that in the Ultra Galaxy series humans are all over the place in space, terraforming away with the technology to create artificial suns.
The fight scenes persist in being cool. Which is only to be expected -- that's the point of switching to green screen and bringing in directors with international, wire-fu experience. That said, these are the kinds of fights I'd envision from beings that are very old, trained from a young age to fight, and have loads of experience. Okay, yeah, the fights are decidedly showy. (No kendou masters facing off standing stock still here.) But it hangs together in a way that looks like the individuals involved are actually fighting, and know what they're doing. The showy parts are backed by sections that come out of Japan's rich martial arts background. And when you get right down to it, it's hard to have beings who can fly, who create light swords out of their arms and not have the fighting be at least a little bit showy.
(For reference, I think the fights in the Star Wars Prequels look stupid. There's showy, and then there's fights that are so showy they're more like stage fencing than fighting. The sword fights in the original Star Wars trilogy, though? Those were done by someone who knows what he's doing.)
As with the last one, my favorite part is seeing Mebi all grown up and being a full member of the Kyoudai. I think in the recent stuff they've done a really nice job in showing him as more mature, and defining his character outside of the context of GUYS. He really can't stay the sweet, innocent puppy-dog we're first introduced to forever. But at the same time they're keeping his innate innocence and belief in people that I think is core to his character.
In this episode more so than the last Mebius is in charge, making the tough decisions. It made sense to me that the others would defer to his judgment on how to handle Mechazam, since he'd been hanging out with him before. The way the relationship between Mebi and Mechazam plays out is pretty paint by numbers for anyone familiar with either tokuzatsu or samurai dramas. But it still worked for me, adding in angst without being (for me) over the top. I thought the end shot with Mebius flying off with the announcer's voice-over about "even today they're still fighting" nice, showing the personal cost of the fighting while underlining the commitment to the struggle.
(Though I can seriously do without the Mebius/Mechazam slash that is, I'm afraid, inevitable.)
As is a theme with the green screened, Power Ranger-directed Ultra series, there are a lot of scenes that are really nice visually. There's going to be a section of the audience that they carry on looks alone, and the looks are strong enough to do it. (Alas, I don't just watch for the special effects; I want some plot and characterization with it.) I'm really enjoying the moments where I watch it and just think, "wow, that looked cool!"
On the "I didn't see that coming", Hikari. I totally thought that would be Zarab-seijin playing Hikari, or maybe mind-controlled Hikari rather than being the real Hikari with a Clever Plan (tm). The whole Mebius figuring out he was faking was a little bit hand-wavy, but is within reasonable suspension of disbelief for this kind of a series under the rules of the "I believe in my comrades!" theme. Hikari doesn't do a lot in this episode, but he gets to look highly cool whenever he does something. Points for that, and for not getting sucked down into the standard "damsel in distress" typecasting he usually ends up having to do.
Also on the "I didn't see that coming", I like that Mechazam is not Zamusha, the robot. They made everything look like it was pointing that way, then took a right turn at Albuquerque.
So, those are the points I liked. On the flip side...
So they pulled off a reasonable reason for why Mebi decides to get the Giga-Battlenaizer. Though I have to wonder WTF King was thinking using a field that suppresses Ultra kousens to hold the Giga-Battlenaizer. That bit seriously made no sense. And it had to have been him, since no one else can get into the Valley of Fire. Other than, apparently, Mebius. Which also seems kind of shortsighted on the planning. It makes it pretty hard to have folks from Team Ultra guard the thing (should it become necessary) if their nifty powers don't work, and only one of them can get near the thing without becoming flambeed. Tsuburaya, can you do me a huge favor and please stop it with the completely nonsensical stuff with no explanation? The 8 Kyoudai movie was one thing, but now there's this, and how Zero ended up getting to his age without knowing anything about his father (with NO EXPLANATION) and it's getting to be too much. You clearly can think things through, so please do so on your modern plots as well.
Also on the "that makes no sense" side, why did Hikari have to use the Giga-Battlenaizer to get rid of the special field up on the surface? If the field around the Giga-Battlenaizer was what was causing the Ultras' kousen not to work (and, again, WHY???) then when Mebi and Mechazam take it out down in the valley it should have ceased its effect upstairs as well. I've gone through the episode several times now and am still missing why that was necessary. Maybe it's one of those things where it gets explained and I missed it (which I have found happening in modern action films), but feh.
I have to say the bit where Mechazam is running upside down on that walkway is, in my book, as dorktastic as Superman!Ryuu flying through the sky. Maybe it looked cool (maybe?) but it made no sense, and the WTF factor was too high.
On the WHY ARE YOU STUPID??? side, seriously, why does no one go looking for the Giga-Battlenaizer at the end?!? Major important uber-mcguffin and we're all going to forget about it and go on our merry (or in this case, angsty,) way? WHY ARE YOU STUPID??? It's a good thing I always watch through the credits or I would have missed the last scene at the end. Which at least resolves the "gee, major important mcguffin and the writers seem to have forgotten about it as well? WHY???" Oh, and incidentally, connects this with the movie. (Admitted, you have to have either seen the movie or have Teppei-level ID Monster skills to know whose arm that is.)
Despite my complaints, I liked it, and like it more the more I think about it. Particular since, in retrospect, part of my "argh, why are you not watching the mcguffin like a hawk and handing it back to Ultraman King at the end to Do Something Useful with it???" is because I know what happens with it next. And the bits that I like are big enough payoffs, for me, to make up for the bits I think are on drugs.
One last comment, which is spoilery for the new movie...
Eh, I'll leave a little more space for anyone who's seen Ghost Rebirth but not the movie yet and wishes to remain unspoiled. Though if you've seen Ghost Rebirth and read any descriptions of the movie (or watch the trailers close enough) it should be pretty easy to put two and two together. Nonetheless...
So... Mebius fetches the Giga-Battlenaizer from where Ultraman King put it for safekeeping then doesn't retrieve it afterward and put it somewhere safe? That means he's basically responsible for Belial getting free and his planet getting frozen and all his people nearly getting (pardon the pun) permanently iced. Nice one, puppy. Now it makes sense to me that you end up being the one to drag around fixing the mess. Now I have a wee bit less sympathy for how beat up you get in the movie.
(Admitted, his sempai really should have made their wisdom rolls and went "shouldn't we find that Giga-Battlenaizer? Since it's a really powerful, dangerous object created by someone who hates our kind and wants us all wiped from the universe?" Yeah...)
Oh, and I guess Hikari does share some of the blame, since he was in on the Clever Plan (tm). But still... WHY DIDN'T ANY OF YOU GO GET IT?!?!!