Not a post about the overall quality of the movie, just how Dyna-related stuff is handled. Little to no actual spoilers in this post, too. (Note:"Dyna" with italics refers to Ultraman Dyna, the series, while without italics refers to the character.)
Dyna gets to be absolutely awesome in this movie. Even in the opening scene, he's presented in such a grand manner. It's also a nice reminder of the sheer size and power of an Ultraman. Really, a good chunk of the movie tells you just how awesome Dyna is. Which would probably be a little confusing for anybody who hasn't seen Dyna's series. The movie talks him up so much, and I imagine it could be a little hard to really care about him if you haven't seen his show.
But anyway, what Dyna/Asuka actually does in the movie is pretty cool, and its enough reason to at least watch the movie once. Well, at least for me, but then I'm biased. Amongst all the Ultramen in this movie, Dyna is really the one who gets the most attention and respect here. Even though the audience follows Zero and his new human host, the movie really devotes more energy to convincing you how cool Dyna is. It's like the script itself is a major fanboy. And I'm okay with that. Dyna/Asuka is actually absent for a good chunk of the movie but even when he's not there, he really shines.
Speaking of Zero's new host: he's Taiga, a new member of Super GUTS. The movie pretty blatantly tries to present him as somebody a lot like how Asuka was, which just didn't go very well. For one thing, it makes him more than a little overshadowed by you know, Asuka himself. He also comes off as annoying, mainly because of how the character was handled, and his lame voice. He could have been more likeable if he actually had teammates to interact with, or something.
As for the characters who were Super GUTS members during Dyna itself, they appear in the movie, except for Mai and Hanejiro. Kohda and Hibiki apparently have been promoted to positions separate from the team, while Ryoh is apparently the captain. There's a scene during the credits with (most of) them, and it's sort of of a follow-up to the "Urutora no Hoshi" scene from Dyna's finale. Speaking of which, this movie does have a big spoiler for it.
There's a minor appearance by the Spheres (spelled "SPHIA" for some reason), but it felt kinda pointless as they could have used some other enemy for the scene.
Besides the characters, there's some nice use of Dyna-related music. We get two covers of "Kimi Dake o Mamoritai" in this movie. The first is by one of the Team U girls, and it has an almost lullaby-like feel to it. I find that suitable, considering the lyrical content (the translation of which I only know from the old Absolute Ultraman! website). Quite a bit of the song is basically "don't be scared, I will keep you safe," which works for the somewhat maternal quality. Later in the movie, there's a more "heroic" cover by Takeshi Tsuruno, aka Ultraman Dyna himself. It's kinda kick-ass, but really one of those things you can only appreciate if you already like Dyna. Honestly, I can't help but feel that the movie could have been improved if they used even more Dyna-related music. Maybe have "Ultra High" playing during Zero's fight against the Legionoids, or use "Takeoff! Super GUTS" when Taiga pilots the Guts Eagle Alpha.
Overall, Ultraman Saga may not be all that great an Ultra movie, but for somebody with a degree of attachment to Ultraman Dyna, some aspects of the movie are delightful. You'd probably be less disappointed if you watch this for Dyna compared to watching it for Zero or Cosmos.
Ultraman Saga is © Tsuburaya Productions
Minor note: why is Asuka still wearing (what appears to be) the exact same outfit he was in when he disappeared more than a decade ago?