Ben 10 - Underworld is a Shooting game. You can play Ben 10 - Underworld in your browser for free. Kevin suddenly appeared and kidnapped Gwen.He demanded that Ben turn over the Omnitrix.If his demand is not met in 24 hours, he`ll kill Gwen.The only way to find Gwen is to fight the way through the massive underworld before it`s too late...Good luck Ben, this is a one-man infiltration mission.Gwen is waiting for you at underworld`s end...