You did start it at some point, or else you wouldn't have any achievements unlocked in it (check screenshot). If you don't remember anything about Alien Swarm, it's best you re-lock all of the achievements you have in it.
It would go quicker if you could also look through your history and list all the games that look weird, and what you remember about them.
What do you remember about Adventure Capitalist (https://www.exophase.com/game/adventure-capitalist-steam/achievements/#906987)? More than half of the achievements have been unlocked with a duplicate timestamp.
It would go quicker if you could also look through your history and list all the games that look weird, and what you remember about them.
What do you remember about Adventure Capitalist (https://www.exophase.com/game/adventure-capitalist-steam/achievements/#906987)? More than half of the achievements have been unlocked with a duplicate timestamp.