This review is based solely on the Movie and nothing else.
Honestly I was disappointed to see this because it is nothing more than a compilation of the first season of the anime, minus some "fillers". I feel the time spent making this should have gone towards a real movie that bridges Season 2 and 3; if there is a third in the making, or could have done a prequal or something to shed some light on what happened before Sidonia was many, many years into it's flight, or what's more, a mash-up of short stories and excerpts pre-Sidonia; such as some of the other ships that went into space, or how humanty was right before the Gauna attacked Earth and such.
For what it is, though, it is a good re-cap for anyone who doesn't want to or have the time to sit down and watch Season 1 of the anime. Most likely, there will be another movie to recap Season 2 sometime in the future, which is sadening since that means Season 3 might be very far off.