Gurren Lagann: Childhood's End is an entertaining and novel recap of the first 13 episodes of Tengen Toppa Gurren Lagann. The movie is an amazing showcase of animation ability, every scene within the film is stunning, and the animation sequences (while sometimes repetitive) are gorgeous. Scenes that didn't make sense in TTGL are removed and replaced with ones that better explain the lore of the series which is a welcome change. However, the film covers 13 episodes worth of content in just over two hours, and so the pacing feels off, and the viewer isn't able to connect to the characters or watch them interact and grow like they did in the original series. To add to this TTGL was always somewhat repetitive and this is further exacerbated by the condensed format which only focuses on the many battle scenes that were the source of the repetitive nature.
If you're a huge fan of TTGL or this film is playing in theaters near you then it is definitely worth checking out. But if you haven't seen TTGL yet, or aren't a huge fan then there's no purpose in watching this film.