This was the first episode of The Flash I can safely say I didn't like. For one, the Zoom explanation bordered on confusing to dumb, especially when Hunter was saying stuff about convincing his younger self to die. I mean really? It's that easy to go back in time and tell yourself you should die now? Also, Barry in the last few episodes has come across as arrogant and stupid. Maybe Harrison Wells/Reverse Flash was good to keep him grounded so he doesn't do anything foolish but I would think after being the Flash for a long period of time, Berry would know a thing or two and become smarter because of it.
Also, this episode was a symptom of a larger problem I have with season 2. There's really no "Holy Crap" moments this year like there was last year. Maybe it's because of all the hiatuses, or maybe it's because when I saw season 1, it was during the summer and there were no breaks, but at this time last year I couldn't wait till the new episode to find out what happened next. I think it was about the time last year when Barry time traveled for the first time that I was like, yeah this show is pretty cool. This year the time travel aspects have made the show confusing. They're talking about time remnets and killing past selves, and I'll say this, Zoom was a whole lot more menacing earlier in the season when he was kicking Barry's ass up and down Central City. What happened to That Zoom. The follow through has left a lot to be desired.
In terms of the whole Supergirl thing, that didn't piss me off, but it irked me quite a bit. You'd think even if he had come back at the same point in which he left, he would have been excited at the experience he just had. I mean he went to another earth, helped an alien deal with two villains, and came back and not even a peep? Cisco would have had a field day with that. Also, that supergirl episode is no longer considered a Cross over. It was Supergirl with The Flash guest starring. A crossover would usually affect more than one show, but this was only done on Supergirl's behalf.