The game saves online every 15 minutes. So if you close the game and open it again, it is possible to lose a few minutes.
The game also saves locally every 30 seconds, but a local save on the browser can be lost for various reasons. So it is best to save manually online, then wait a bit to make sure it saved before you close the game.
 "Idling to Rule the Gods"){kind=icon}
 "Radical Fishing"){kind=icon}
 "SPACEPLAN Prototype"){kind=icon}
 "Astrox"){kind=icon}
 "Harvest Idle"){kind=icon}
 "Learn to Fly Idle"){kind=icon}
 "Incremental Popping"){kind=icon}
The game saves online every 15 minutes. So if you close the game and open it again, it is possible to lose a few minutes. The game also saves locally every 30 seconds, but a local save on the browser can be lost for various reasons. So it is best to save manually online, then wait a bit to make sure it saved before you close the game.