The new Mandroid showed up; that was too much, too fast. I was looking forward to him basically fully turning himself into a Transformer over time and getting an alt-mode, not turning himself into a weird stretchy monster in a liquid tank. It's like they got tired of that plotline and skipped past to the end, and then kept going. It really felt like they were setting up "Mandroid goes full robot, helps Croft win, Croft turns on Mandroid because he's just another robot, leaving him to choose between helping the cybertronians to save himself, or winding up in the same boat as them." Guess not.
Honestly it really felt like this was the end of the series, not the end of the season. I'm genuinely surprised there's going to be a season 2, unless they just jump straight into Autobots vs Decepticons again for some reason, there's no more villains. Speaking of which, did not expect Mandroid to absolutely murder his human co-conspirator though. That was surprising for a kids show. Like, I didn't feel great about seeing that, I wonder how I would have reacted if I was a wee youngin'.
But yeah, no villains besides the Decepticons - who are too easily made buddy buddy. LIke you show them even a modicum of compassion and suddenly they're all "Eh, let's chill out a bit. Even Starscream. Don't disagree with the message, but that kind of stuff takes timem. As mentioned by others, the status quo has been completely blown up at this point. I'm guessing the healing wave will have also created a bunch more Terrans, and cybertron is still out there, but yeah, weird ending that's probably going to cost this series my #1 favorite series spot in the end, but we'll see how Season 2 goes.