Up until now, I'd avoided this series. Initially, it seemed like something that I wouldn't like to watch, for no reason in particular. Recently, though, a certain reviewer came up with a review of this series, and I, lacking any series to watch, decided to give it a shot. As such, I'd like to start off this review by stating that Gurren Lagann is an amazing anime. It offered three of the most important things I look for in an anime -- emotion, action and raw entertainment. If you haven't seen it already, I suggest you watch it immediately after reading this review.
Gurren Lagann is a story told on a grand scale, large to the extent that it's nearly unfathomable. For years, humanity has been hounded underground by the Spiral King, oppressed underneath the surface of the Earth by monstrous Gunmen, which are essentially mecha, piloted by the cruel Beastman race. Simon, a digger in one of the underground villages, finds one of the Gunmen buried deep underground. With the help of Kamina, his friend and inspiration, and the company of Yoko, a girl with a rifle, Simon is forced to help free the human race from the iron hand of the Spiral King, armed only with Gurren Lagann, the Gunmen produced by combining his and Kamina's mecha. That's only half of the plot, until the series undergoes a time skip after the aforementioned king's defeat. In the end, though, the story that's told is worthy of being considered an epic, spanning decades over the course of twenty seven episodes. As the characters progress in both their attempts to overthrow their enemies and their lives, new cast members are introduced and taken away. All in all, this leaves for a captivating plotline that I can't describe very efficiently. The best way to understand the grandness of Gurren Lagann's story is to watch the show yourself, which I highly recommend you do.
Characters are a strength in this show. Simon's character undergoes one of the most well-done developments I've seen in anime. Starting off as a timid, cowardly digger, he gradually grows into a more reliable protagonist, one that becomes more likable as the series progresses. Kamina, on the other hand, was likable for the duration of his stay. To quote the series, he's the "paragon of manliness", and his speeches never failed to inspire his allies. I'd describe him as the moral support of Team Gurren -- he acts as a badass older brother to everyone in the series, always there for his friends when they need him. Yoko, the third main member of Team Gurren, fights the Gunmen with only a rifle. She's the show's main source of fanservice, although she holds a will of her own and is not, unlike other anime heroines I can name, a pair of walking breasts with a gun. The supporting cast is vast as well, with some characters being more memorable than others. To close off this segment, however, I'd like to say that Gurren Lagann is a show that knows how to kill its characters. The deaths are always either depressing or epic, sometimes a mixture of the former and the latter. As a result, when characters die, the audience perceives the death to its full sadness.
This show likes to invent its own logic. I'm sure that you've heard this already, but Gurren Lagann won't make sense if you take it seriously. Characters' respective fighting spirits are enough to somehow bend the laws of the world through the use of the mysterious Spiral Power. In example, Kamina, piloting Gurren, decides that the most effective way to combine with Lagann is to shove its drill down his own mecha's neck. Through the power of their wills, this somehow creates an exponentially more powerful Gunmen than they had started off with, capable of defeating their foe with ease. Eventually, near the end of the show, galaxies are used as throwing discs in one of the most over-the-top climaxes I remember seeing. Regardless, though, this only makes things ever the more epic. As seen in the case of anime such as Black Lagoon, sometimes realism shouldn't be applied very heavily, if at all, when you animate a show. The mind-boggling action sequences make up for a substantial part of Gurren Lagann's entertainment value; animation is fluid, with soundtracks that manage to get the viewers' hearts pumping.
I can continue trying to describe this anime, but I don't think anyone is capable of effectively capturing the essence of this show in a review. I'd like you to watch this show for yourself. Regardless of how many times I state that the action was fantastic, the characters were memorable or the plot was grand, you'll never truly experience what it's like to watch this show until you actually do so. All in all, Gurren Lagann is an anime that is more or less a must-watch, and I fully recommend this series.