I am a Getter Robo fan so I might be just biased about this, but the ending has been very climactic to me even if it leaves you wanting for more conclusions. I won't add more spoilers, but it does have an extension to its story and a bigger picture to it in the form of the manga, or the SRW games but that's another topic. To get back to it, the ending is pretty much just somewhat of a callback to another anime called Gunbuster, which ironically is inspired by Getter Robo. I want to call this last episode as a good climax to the entire show because of how much it ramps up to 11 with the amount of craziness that the series portrays, and in a way gives Getter Robo an identity of its own that makes it stand out in comparison to its 70s Toei super robot counterparts. I've been a Getter Robo fan for almost a decade now and even still, this show has still a lot more to offer. This is a show that I would highly recommend to anyone wanting to get into mecha.