@realcaseyrollins
Since there is a spoiler tag I can list my grievances I guess.
- first thing would be that black flying mud-hound that brings down blondie. Did you know they could fly? Did they do that before? If so, how common is it? Why did this never happen on screen before?
- Suddenly the hand rails of the bridge between the train cars fold to the side, we've seen combat on the bridges before, but never that it folds to the side.
- I get the broken boot that malfunctions. Its made from surplus materials what the kids could salvage from train cars. What I do find weird is that the boot that is designed to keep the wearer upside down is so easily pulled of by the chick during combat.
- when blondie kicks the chick off the train he is also at risk of lodging himself over the railing again. Physics, mass and all.
- Unless it's part of some storyline or a main character creatures in a train car never leave their home. So when the chick gets kicked of the train a bunch of origami birds haul her ass back to where she started. Do creatures escape more often? We didn't see it before besides the main cast. We didn't see them leave their car, so it felt unnatural for them to appear like a deus ex machina. We couldn't prepare for that.

A minor issue is the sudden explosion of digits on blondie's body. It took the fake conductor a life time to achieve her personal hell, but his... In a new york minute.