Basement Collection - no achievements?

Weird question, but some people do play on different computers, are you sure that the computer you played the basement collection on, had a stable internet connection, and that you were not in offline mode at the time while you were playing it, and that steam was in fact connected?

You need to be online to get achievements , the game is dependant on that. If you get dced while playing bring steam back online

I had this problem one time. Restarting game helped. Although, I had to achieve it once again.

Why do all of his games bug up like this?

I had the same problem with Binding of Isaac.

(ofc I don't have The Basement)

Are you using Mac or Windows?

I had/have the same problem with The Binding of Isaac. "Verify integrity" helped me (right click on the game in your library -> properties -> local files: "verify integrity of game cache..." and/or "defragment cache files").
Next time I started the game, it gave me all the missing achievements at once.

What I recommend is just quitting the game and restarting it. This coming from one whom has dealt with a similar problem in Binding of Isaac vanilla.