Here is the full list of all 7 Project Lounge achievements.
As a host have 7 visitors in your Lounge.
As a visitor spawn an item in someone else's Lounge.
You launched the game at 1AM. Sure you shouldn't be sleeping?
Fall out of the Lounge... and go back to where you came from.
Press apply button at least once in Options Menu.
Pick up an object for first time.
Save your very first Lounge.