Roblox is a game creation platform which allows players to create their own games using its proprietary engine, Roblox Studio. Games are coded under a object oriented programming system utilizing the programming language Lua to manipulate the environment of the game. Roblox hosts social network games constructed of Lego-like virtual blocks. [source]
Fortnite is an online video game developed by Epic Games and released in 2017. It is available in three distinct game mode versions that otherwise share the same general gameplay and game engine: Fortnite: Save the World, Fortnite Battle Royale and Fortnite Creative.
Players can use their pickaxe to knock down existing structures on the map to collect basic resources that are wood, brick, and metal. [source]