The first few episodes may seem like setup for a generic kaiju show, but the story does enough to tweak the kaiju/toku formula and does something new. The characters are actually realistic and likable and the fight scenes are fantastic.
The animators aren't afraid to use CGI, which I know can turn some people off but it blends well with the 2D animation. The fluidity and fight choreography is eye candy. If you're a fan of action anime with a great soundtrack, you can't go wrong with Gridman or its sequel Dynazenon.
