A sandbox map is a open-ended gameplay map, there is no objectives to complete and you havee access to all the units, like for example, Command and Conquer generals, you fight against an AI opponent until you defeat him, simple as.
Sandbox Skull Effect: The Effect of the Sandbox Skull is unknown. There may be no effect whatsoever. Finding the Sandbox Skull will unlock an achievement worth 25GS. Sandbox Skull Location: The...
There is no sandbox mode in 2. You can go into scenario editor and tediously select the entire map as being owned, then pick the rides you want to work on- as well as the scenery you wish to include...