This movie is a mess. Scooby Doo doesn’t deserve this script treatment. It’s not even a Scooby Doo movie - it’s a robots and explosions Hanna Barbera mash-up movie that is poorly executed. Will Forte is a terrible Shaggy (was Matthew Lillard unavailable?), Fred became Zac Effron rather than being Fred (and the only Fred is the amazing Frank Welker). Ken Jeoung as Dynomutt was about the only good casting (saving grace is they did hire Welker to voice Scooby - who did take over for Messick in the cartoons).
If you have young kids, they’ll enjoy the silliness. But if you’re a Scooby fan - skip this mess and e-mail Warner Bros to complain how they handled one of their most valuable properties.