What Does Sandbox Mean?
A sandbox is a style of game in which minimal character limitations are placed on the gamer, allowing the gamer to roam and change a virtual world at will. In contrast to a progression-style game, a sandbox game emphasizes roaming and allows a gamer to select tasks. Instead of featuring segmented areas or numbered levels, a sandbox game usually occurs in a “world” to which the gamer has full access from start to finish.
Techopedia Explains Sandbox
Sandbox games can include structured elements – such as mini-games, tasks, submissions and storylines – that may be ignored by gamers. In fact, the sandbox game’s nonlinear nature creates storyline challenges for game designers. For this reason, tasks and side missions usually follow a progression, where tasks are unlocked upon successful task completion.