No more manual structs!

//obj_saveload create event
global.levelData = {}; //Initialize empty struct, leave it completely blank!

//--------save_room function
function save_room(){
    var _room_struct = {
    }

    //Save all of your things here normally, like in the video.

    //Store room NAME struct in global.levelData
    global.levelData[$ room_get_name(room)] = _room_struct;
}

function load_room(){
    var _room_struct = 0;

    //Simply get the levelData from the room's NAME we are in!
    _room_struct = global.levelData[$ room_get_name(room)];

    //Just in case some weird stuff happens, exit!
    if(is_undefined(_room_struct)){
        exit;
    }

    if(!is_struct(_room_struct)){
        exit;
    }

    //Load all your stuff here, like in the video
}
//The save game and load game functions stay the same. Now you won't have to worry about creating a new struct for every room!
//Remember: Once you release your game, you cannot rename your rooms, or any assets really, as this will absolutely cause save file corruption and your players will be very angry!