https://www.scirra.com/tutorials/526/ho ... -savegames
[quote:32tpu308]'No Save' behavior
Anything with the No Save behavior will not be saved, and won't be affected when loading. It is good practice to add the No Save behavior to any static objects, such as scenery and backgrounds. It can also be used on automatically-updated objects like the HUD and text objects which are updated every tick. This won't make any difference to the game, but it makes savegames smaller and faster to save and load, since the unnecessary information is omitted. (It's also necessary to make continuous preview work effectively.)
Changing the project after saving
Savegames should be robust to changes in your project. You should be able to add, remove and reorder various things like variables, behaviors and other objects, and still have old savegames load successfully. Note however anything new you add won't have save data for it, so will not be affected when loading. Also note if you remove anything from the project it won't be able to load again either. You can delete individual instances without affecting savegames, but if you remove entire object types, layouts or layers, they will never be loaded back from a savegame.