Firstly, I know how hard it is to animate in SFM and all that other stuff, so no complaints from me. In fact I think it was well-animated and well-paced. Nothing more I can say here. Now with that out of the way, EoTL just did not live up to the hype. That's my opinion and opinion is not fact and I'm not going to treat my opinion as fact.
There were a lot of things that bothered me and kept me from enjoying EoTL, but I'll go to what bothered me the most: Heavy and Demoman. I will say that it's rare for an official work to be weighed down by fanon and yet here I am seeing EoTL treating both Heavy and Demoman the way that fandom does. Heavy in EoTL seemed to be portrayed as a mentallly challenged manchild despite that he is actually one of the brightest mercenaries in the group. Demoman is just drunk and passed out thus out of the way--like in most fan fictions. Never mind he's not drunk all the time and still has a job to do.
And speaking of Demoman, wouldn't him and the Engineer make a better team to try and stall the train? I mean if we stopped making Demoman a useless drunkard and focus on his skills as a demolitions man, he'd surely know about disarming bombs. As for Engineer, he'd certainly know how to deal with a train. Two VERY important guys on a TEAM of nine experts, and yet these two--especially Demoman--practically don't exist or do anything important.
Not only that, but I felt that the team characterizations were off--everyone knows that BLU is less cunning and more accident prone than RED. Yet BLU comes up with a plan and comes off as ridiculously badass? What.
Whatever. I knew EoTL was not going to be good since the cover had only 7/9 mercs present. Can't say how I came to that conclusion. It's possible I was expecting to be let down or had too high standards, but it pretty much was bad.