Sandbox games can contain structured elements – such as mini-games, tasks, submissions, and storylines – that players can ignore. In fact, the nonlinear nature of the sandbox game creates a challenge for game authors. For this reason, tasks and side missions usually follow a course in which tasks are unlocked after successful completion.
The game types of the sandbox game are different. Massive multiplayer online role-playing games (MMORPG) generally include a mix of sandbox and progression games and depend heavily on the emergence of interactive user gameplay to keep non-progression-focused players.