Hello ! I recently really enjoyed a game on steam that is called "Seen" and I really want to speedrun it. Can you add this game here ? Thanks !

You can request the game yourself in the support hub.
However, note that it might not be accepted yet because the game is in early access, and might be subject to future changes.

@Oreo321
3-4 ish months ago one of my friends tried to request the same game, it got rejected because the full version of the game is not out yet.

@Tweek_CornFlex
This means you pretty much have to wait until the game is not in early access anymore to successfully get the game on the site.

I'd say still give it a try as the rules for what games are added have become more lenient, just don't be too disappointed if it gets rejected