Both shows revolve around a teen boy who leaves his village, finds a giant mecha, and pilots it. He later finds a mysterious girl who becomes his love interest and is not all that she seems to be. Halfway through both shows, there is a timeskip and thus the characters are shown older. Both shows begin with small-scale conflicts and slowly escalate into much higher stakes, with political themes involved, and the mechs just keep getting bigger. Near the end of both shows, a character is fired out of a giant cannon while in their mech. Zoids is not as over-the-top, but still contains plenty of explosive action scenes.