Hello, I bought the game, is it possible to key for steam?
Game was purchased on email - firstname.lastname@example.org
Claiming a free game is different than buying. The developer previously announced in the comments that Steam keys would not be included when claiming the game for free.
If the developer wants to share Steam keys then they'll add it for people who have purchased the game through itch.io. If they add keys, they will be claimable from your download page. Please avoid posting your email address in the comments.