If you're thinking about using this as an introduction to Penguindrum: don't. These movies are, by necessity, an incredibly abridged version of the Penguindrum story. They took out a lot of the worst parts about the show, but they also took out a lot of the best parts as well. Part of the fun of Penguindrum is the slow descent into the story and detailed build-up followed by the satisfying pay-off, but these movies go at an absolutely breakneck speed the entire way through. It does not give the viewer room to ponder the questions which the story presents, before either shifting to an entirelydifferent scene or immediately answering the question that was presented. If you want to watch it as an introduction, it will make almost as much sense as the original (which, to be clear, is not much!) however you will miss out on a lot of the emotional payoff of the show's format.

That being said, if you have seen Penguindrum in the past and want to re-watch some of the best moments of it without watching the entirety of the show again, the Penguindrum movie is for you. Some scenes are shifted around from the original, and there is a bit of added content, but at its core, it is mostly the same. Unfortunately it does not expand much on the source material, since so much of the movie is just a rehash of the original show with less emotional impact.

TL/DR: It is an inferior, but a lot faster, experience to the original show, overall.