The acting from the main cast was pretty good. Supporting actors....not so much. There were a lot of high-school stereotypes and a lot of unoriginal dialogue. The movie lacked substance, but that is how a majority of DCOM movies end up.
As for positives, the idea of time travel isn't original, but the take this movie took on it was: high school seniors using time travel to fix embarrassing moments in their fellow student's lives.
In the end, I wouldn't re-watch this movie, but it was an enjoyable one.
(Full review coming soon - with better wording probably)