A Roblox account belonging to the Canadian mass shooter was discovered by the internet forum Kiwi Farms last night. One of the games created by the shooter is a mall shooting simulator, modeled after a real mall in Canada, where the player can fire into a crowd of terrified civilians.
At the time of writing, this game can still be downloaded by users of all ages, regardless of parental controls. Roblox deleted the shooter's account but left the game up.
Credit to @realRubenSim for finding the game