How exactly Steam Cloud works ?

[Que]

This is quite confusing to me ...

So , I'm playing a game named Moonscars , and this game has a pair of achievements which you can only get one of them on one playthough , but according to a guide you can get both of them , if you tinker with save file and steam cloud .

So , I experimented if this actually works before doing achievements in case it doesn't work .
I disabled steam cloud , copied save file and left it on desktop , launched the game and added certain change , them closed the game and deleted current save file , replaced it with old one .

However when I relaunched the game , the change I added to new save file was still there , while it was supposed to be back to the old save file's state , because it IS old save file .
Shortly after I enabled steam cloud just in case , but it didn't change anything.

What do I not understand correctly ?
I didn't lose any achievements since it was merely a test , but I want to know how it works .
It depends on games ?
Or steam cloud have nothing to do with it , and it is just a matter of save files ?

[Iceira]

Yes its time stamp, what prevent you make new save and do as you see fit. ( all it do is sync newest time stamp on a file. load old game, make new save then that is active, its rare its bound under a profile in top of this, some game do this.


ps.
and why so many explan this is not a backup Solution this is a cloud sync only.
but many dont get it ( and we take it one more time what prevent steam make a corrupted save game file as newest then game is make the error , nothing. )

pretty sure its rare, but could happend.

[Que]

So what happened to my old save file wasn’t supposed to happen ?
The old save file’s state was supposed to remain as it was ?
And it’s a rare case , hmm … I got it , thanks .

[Dr.Shadowds 🐉]

How cloud save works, it has meta data on your files, it matches with the cloud, if it different it be replaced, or verified.

- How to replace/remove save file please note this replaces/move save file on the cloud, to do this, launch game, alt + tab out of game, you replace/remove the file's, then force shutdown game, this will update the cloud to replace/delete said save file.

- How to use multiple saves for a game that only uses one same file, just turn off cloud save for said game, can do this by right clicking on game, click properties, then uncheck box for cloud save. Then you manage the saves yourself by swapping them how you see fit.