Gurren Lagann has had a number of extra animated shorts and side episodes produced for release on DVD sets or bundled with other products, including 15 "Parallel Works" music videos, a 12-minute episode bundled with the DS game, a video manga called Viral's Sweet Dream, and a director's cut version of episode 6.
There's a Yonkoma in between every chapter of the manga adaptation, along with various extra chapters that explore the characters, such as Kiyal's comedic rebellion against Dai-Gurren, Yoko attaining her own Gunman, and an encounter with Nia's older sister.
Cast the Runner-Up: Crispin Freeman is the new voice of the Anti-Spiral in the movie dubs (since Dave Mallow retired) and he was previously slated to voice Kamina before Kyle Hebert got the part.
Dear Negative Reader: Osamu Kobayashi was the guest director for episode 4. His look for the characters and animation style received some criticism from 2ch when it first aired. Producer Takami Akai made a disparaging comment about said criticisms (he said it was like putting your face next to an anus and breathing deeply) and resigned his post as a result of the fan backlash.
Dueling Dubs: In Russian. Reanimedia's highly praised dub has been around since 2009, yet Fan, a newly established satellite network, chose to air a different one (distributed by Wakanim) in 2018.Though they do overlap.
Missing Episode: Most of the entire English dub produced by Animax is lost, with almost no footage or audio of it anywhere. The dub for episode 11 would resurface and be uploaded to the Internet Archive in 2020, but the other episodes remain lost.
The reason Bridget Hoffman filled in for Hynden Walch as Nia's Time-Shifted Actor was that Walch had personal matters to sort out and had to drop out of the show. It works better than most examples since Nia is a slightly different character now that she aged. In turn, the dub cast list for the movies lists Hoffman as Nia's only voice meaning she'll be also be taking over from Walch in voicing Nia's younger self in the first film.
Dai-Gurren's helmsman, Gabal Docker, was voiced by Steve Schatzberg for volume 3 but was recast with Joe Ochman for his later appearances due to Schatzberg's death from cancer in August 2008. It was Schatzberg's final voiceover role. For his final appearance, the role was once again recast with Keith Silverstein (Makken). Ochman returned to voice Gabal in the movie dubs.
Due to some actors’ retirement over the years since the TV series came stateside, the dubs of the movies have their share of recasts. Amber Lee Connors is the replacement for Mari Devon (retired after 2021) as Cybela, and Crispin Freeman replaces Dave Mallow (retired in 2017) as the Anti-Spiral.
Refitted for Sequel: In the original TV series, there just wasn't enough time or money for the animation team to put in everything they wanted, which is why so many of the cast were killed off. Thankfully, the series was successful enough to warrant film adaptations, and the second film includes all of the content they originally wanted to add in.
Studio Hop: At first, the North American releases of Gurren Lagann were going to be handled by ADV Films. Following ADV's liquidation, the rights were picked up by Bandai Entertainment. Then, Aniplex of America picked up the series after Bandai's rights expired.
According to an interview with Anime News Network, the staff had originally wanted to spend a couple of more episodes exploring what it's like to live underground, but they weren't able to due to time constraints. Likewise, they also wanted to spend more time exploring Simon's imprisonment and his time in jail in the second half, but those plans were similarly scrapped for the same reasons.
Back when the show was originally announced, then-Aniplex president Koichi Natsume stated in the show's initial announcement that "there may be multiple sequel series". However, these plans never came to fruition. According to Gainax president Hiroyuki Yamaga in a later interview, the creators and staff did want to do a sequel or prequel series after the show's conclusion, but those plans were ultimately scrapped in favor of the two Compilation Movies.
In Bandai Entertainment's English dub:
Crispin Freeman was going to voice Kamina before Kyle Hebert got that role. Crispin years later would be cast as the Anti-Spiral for the dubs of the compilation films due Dave Mallow retiring in the intervening years.
Steve Blum also intended to voice Kamina until he saw a picture of Leeron. The producers were unsure about having Blum voice Leeron, but let him audition and were blown away by his performance.
Writer Conflicts with Canon: An early press release states that Yoko and Simon are both 14 at series' start, while Kamina is 17. In series, there's nothing stating specific ages, nor any implication that the characters' appearances deviate from them. People going off the show itself almost universally perceive Simon's attraction to Yoko as a Precocious Crush on a girl much closer to Kamina's age.
Made its debut in the Super Robot Wars series in The Second Super Robot Wars Z: Hakai-hen, and remained a mainstay for the rest of the Z series, each installment incorporating elements from both the TV series and the movies. Of note, it was arguably the most important series in The Third Super Robot Wars Z: Jigoku-hen where its final arc takes center stage. It also appears in Super Robot Wars OE (although it's only Simon, Kamina, Yoko and Viral from a very early point in the story), Super Robot Wars X-Ω, and most recently its post-timeskip arc/second movie was covered in Super Robot Wars X. The series is also notable for being included because when it's involved, Tengen Toppa Gurren Lagann is usually the most powerful unit in the game.
They have a point, since the movies are essentially abridged recaps of the TV series with some slight (if not fan preferred) changes and new animations. Aniplex USA later dubbed the films for their 15th anniversary 4K screenings