I know there is no standalone creation in max yet but when it is put in, I was just wondering if there is any planning on how the save and load game progress will be implemented. I hope it will be a totally new system of saving the players progress, classics system does not remember the state of locked doors, and whether entities have moved, etc and a lot of lua has to be added by the user.

It should be a standalone window setting.
Keeping the current progress shouldn't that hard since GG does something seemed with the checkpoint system, although it is not implemented in GG standalone.
Also, there is something to take care of as well, I'm going to explain to you all to get my point.
I have a Z lotion, if you own it and use it, you will be able to walk with the zombies without getting hurt, although it has duration time, if the effect finishes and you aren't done, you (the player) die.
Ok, the player dies, however still has 2 lives, so try 2, start to try 2, and man, the Z lotion is no longer there, therefore the player doe not have the z lotion, therefore he is unable to walk with the zombies, therefore the game end, because the engine does not reset all the level and start from scratch, so the player will have a second chance to try to.

Both great ideas. I haven't heard of the checkpoint system. Interesting- what is it?
"the engine does not RETAIN in-play variables, instead it RESTARTS everything from zulu hour (scratch)"
According to what I've heard most people say regarding saving these variables;
make them global-carry-over variables (just global is not enough?) by using the
famous and glorious g_ yourvwxyz Ex; g_lotion. Anybody tested/ know of updates?

Yes I have written 2 lua scripts to save and load these variables, and also in those lua scripts they also ensure that entities that are moved, things collected etc are correctly re-loaded, it works, so I guess this will be the same in Max. These scripts are not generic, and have to be updated as you are creating your game. It's a workaround but it does work well, plus I can save and load progress and changes during test game as well.

It can be done via LUA of course, I myself had played some time with load/savegame; anyway, the point is, it should be integrated into the engine itself, so you do not need workarounds.

@GubbyBlips
A lot of time do not mess with GG; anyway, you should have a checkpoint in the entity panel>markers. Even you have the checkpoint function in global.lua file.