I should have nearly all the achievements on steam because I was very far in my account before I linked it to steam. But since it is a linked account, I already earned those achievements and they weren't awarded on Steam. Is there something that is going to be done so that those of us who earned achievements on other platforms have them carry over to steam as well? I wouldn't mind getting those achievements again but I can't replay the levels that I already beat.

Yup. I only have 2 and they are the ones I've got since playing it on steam. I don't even have the "getting started" achievement. Maybe I should note that the first day I tried to transfer my data to steam, I got it transferred but when I closed the game and opened it again and hit start, it gave me an error message. It happened a few times so I stopped trying, then tried again a few days later and it worked fine. Perhaps something with the error message stopped me from getting my achievements.