Boosteroid uses the cloud storage (synchronization) mechanism of other game platforms, where it’s possible (e.g., Steam, Origin). In order to have that mechanism work out, you must correctly complete your game session on Boosteroid through the “quit” button in a video game, wait for the desktop to appear, and then end the session.
For the Steam, Epic, and Origin launchers you need to check if the cloud synchronization mechanism is enabled (usually enabled by default). Here's a video that shows how to enable cloud saves for a specific game.
Moreover, you can check an additional article for all the details regarding Steam Cloud Saves.
You can also manually trigger the cloud synchronization process on Steam and Epic Games.
On Steam: click the "cloud" button before launching the game from the library.

On Epic Games: after closing the game, go to the library and find the game you need to sync saves on. Click on the three dots below the game icon, choose "Manage" and select the appropriate action.

In case the "Cloud Sync Conflict" happen, you always need to choose the first option "download to this machine", despite what save file is marked as "newer".

Not all video games support the option of cloud synchronization. For example, the demo and trial versions of video games do not support that function.
For video games where the cloud storage mechanism is not supported, Boosteroid saves the user’s game data and sends it back at the beginning of a new game session on Boosteroid.