The first and only Gamera film in the Millennium series (and also his last film up to this point) will easily turn on your kid perspective and enjoy a kind-hearted and delightful Gamera film, cheesy enough to love and not enough to puke.
Gamera: The Brave starts right off with the sacrifice of the title monster in order to eliminate all the Gyaos that invade random Asian area no.51 in these movies. Years later, a little kid (our main human character) finds an egg that quickly grows as days go by, until he realizes this egg is actually a new Gamera, which he names "Toto". As expected, this film is more kid friendly than the previous trilogy, and goes for a more safe point of view and execution. It doesn't show anything new, it certainly isn't the best Gamera film, but it's entertaining to watch. There is the requisite monster action and delightful cheesiness to hold up. This feels different from other films in the series, while also still being true to it at the same time, so there is a no-cop-out factor here. The best way to enjoy this movie is having a kid's perspective, without asking too much complexity or achievement in a movie like this, just enjoy what's there to enjoy.
No film of Gamera has been produced since this. The series had been on sleep since 2006, and I think it is proper time to give the turtle monster a new reboot. Maybe even a Godzilla vs Gamera, who knows. Overall, this movie is light and safe, but entertaining and good for the kids.