One of the spots I have issue with is basically right at the start with the Cat's Lair. It kind of feels too "smooth" for me? Too plastic-y? It looks less like this giant ancient monument and more like a enlarged toy. I think if they gave it a bit more texture with the coloring then maybe it would feel a little better to me. Maybe change the proportions a little, too. But, that's a nitpick, I'll admit.
But, I do like that we find out about their "faceless god" Thundera. That's a interesting bit of world-building. I hope that gets fleshed out a little more down the line, somewhere.
Cheetara and Tygra seem to have had a crushes on each other even back when they were kids. That's kind of cute. I'm rooting for these two.
We get to see baby Lion-O and...he kind of looks like a kid who got his face painted? It's cute, and I don't know how else you could have done it. It just looks a little less like "fur" and more like "facepaint". But, that's not the part that I'm going to complain about.
No, the other part of the artwork I have issue with is this version of Snarf. Snarf looks like a tiny hairy man in this art style. It's the "flesh" around his eyes that's doing it, I think. But, he does have more human-like proportions in this art style, too. Instead of looking more like a animal like in the main book. It's off-putting. I don't like it.
Claudius going blind after a fight with the mutants (sorry, Mu'tants) is another nice little world building moment, though. Although, his pet saber-toothed tiger looks surprised to get petted in one panel. It's kind of funny looking.
And we get a look at ALL the Thundercats as they were back on Thundera. Pumyra, Lynx-O, and Bangali are here! Which makes me wonder where they are in the main book. I hope they didn't die on Thundera, later, in this universe. They're probably fine.
But, yeah, everything's going good until Cheetara gets a vision of their world exploding in the future. So, that's not great, even though we knew it was going to happen. But, it makes for a good cliffhanger for this issue. We knew it was coming, but it'll be interesting to see how Cheetara warns everyone else. It's a solid concept for a mini.