I also really liked the first episode, and the second which just aired!
It was a very interesting change to have an Ultra show start off with the main character already having been a host for some time, along with Ultraman being known to the public and having fought multiple monsters (including Red King and Gomora!) prior to the events of this episode. I'm not sure how many times that's happened in series history, but it was definitely a cool way to switch things up for me, and a great way to hit the ground running. That monster from the opening kinda looked like a cross between Zetton and Antlar too...and I guess that's not the last we'll be seeing of him....
You can definitely see the Return of Ultraman influences in places, and it was cool to have an Ultra saying "shuwatch" again!
They did a good job of introducing the cast, and everyone seemed likeable. And that big fight scene again Shagong - which was itself a cool creature with some neat abilities - was awesome! I loved the part where the camera rose through the building as Arc was getting up. Very, very cool.
In fact, both of these first two episodes have had some really imaginative fight scenes. I hope this is indicative of what we'll be seeing going forward with this show, because if so it would seem as though the theme of "imagination" is being used in some great ways!
So yeah, a really good start to what's hopefully going to go on to be another great show!