If we have robot enemies in our game, is it okay to have them dismembered, decapitated, impaled and all that stuff? Something along the lines of the children's cartoon Samurai Jack. No humans/organic life would be given this treatment.
Yes, you can see descriptions of allowable content for PG-13 films here https://rating-system.fandom.com/wiki/PG-13_(MPA) . Robot violence certainly falls within this category, and would probably even work in a PG film if it's considered fantasy violence.
