I just watched the Flash and was pleasantly surprised. If they'd made a few small tweaks it could have actually been good:
1. They needed to cut the length down by about 10-15 minutes.
2. The effects needed to be finished. They weren't as bad as I was expected, but there was definitely a couple of scenes where things looked kind of cartoony. It reminded me of the Matrix sequels. Where things were generally good, but then you'd all of a sudden be watching a cartoon.
3.