Killer.io is a multiplayer killer simulator Game. Become a silent killer in the middle of the Halloween party. Kill and hide bodies in this fun online murder game. Try to kill as many people at the Halloween party as possible. Try not to get caught! Killer.io Game is one of our Action Games at Round Games. It also tagged as a IO and Multiplayer game. To play even more free games, view our most played and all games pages. If you want to play more games like Killer.io Game: Then you can simply check out the games inside the game tags that are the most relevant to your interests or check the Action Games category or check the related games section at the end of the game page.