I want to know exactly why Sandbox+ doesn't work (I don't own Remastered) so I made a simple test script.
Upon loading a saved game, it should display "HELLO WORLD!", teleport you to Boat Dock, and gives you 5 stars police wanted level.
If this script works then I suspect they removed some functions like "player_button_is_pressed".
If a Hello World message shows up but doesn't teleport you, then they removed teleport functions.
If it doesn't work at all (not even a Hello World message) then it could mean any of the following:
* message function got removed
* sr3_city_main() is not called by the game anymore (it was a blank function in the 2011 vanilla so they may have decided to not bother it)
* sr3_city.lua is not loaded by the game; the game lost its ability to load loose lua files (only xtbl is loaded)
* The contents of sr3_city.lua is drastically different from the original (2011) version.
* The game doesn't use Lua anymore; missions are now hardcoded in C++ (I heard Agents of Mayhem is apparently like this)
I also want to know if game_lib.lua is loaded by the game, so I uploaded a modified game_lib.lua.
If the first enemies in the first bank heist mission shows health bars, then game_lib.lua is loaded by the game and the missions still use Lua internally.