"Compound" is NOT A MOD. Written in C++ and DirectX, it is an isometric, single-player computer role-playing game (cRPG) taking place in a desolate setting. It has been in development since 2007. The game is influenced by a number of the gameplay philosophies used by Fallout; however, it neither shares Fallout's universe, nor is set to exactly replicate Fallout's gameplay mechanics.
This video demonstrates upgraded travel on the BIG MAP(tm). It now zooms in and out, the player leaves markers and trails.
It ends with an imitation of a random encounter from Fallout 2, which demonstrates the scripting system. Nothing about that encounter is hardcoded into the game's executable - it is all in external script files.
Before, such customized encounters weren't possible. You could only encounter hostiles roaming the map, and if you're very, very, very lucky, you'd get them at an interesting moment... but now encounter maps are spawned and start exactly defined scenarios - just like in Fallout 1 and 2.