Gurren Lagann is an essential anime for not only fans of the Mecha genre but people who enjoy over the top story telling in general. The show takes a stale trope like the "hero with a heart burning for justice" and is able to interject life into it. The hero has a burning heart? Then make it be the power source that he can use to become stronger and energize his giant robot!
The show has a a great mixture of these over the top bits of action and real human emotion. The highs of this show will get your heart pounding and shouting at the screen in joy. The lows will have you crying your eyes out as you feel the pain that the rest of the cast has to endure.
The show’s only real downfall is its ending. Thought it does have a lot of great moments as it wraps up, it still leaves you with a wanting the ending of a certain character to be different. No spoilers though.
Other than this minor detail with the ending, the series is still an incredible entry to the Giant Robot genre. Anyone who says they are a fan of Mecha needs to see this show to be able to back up the claim.