Game not on giveaway list?

That's because it has been given away for free on Gleam few weeks ago.
You cant giveaway free games...

It was given away for free from gleam, at least twice. Games that have been given away for free, in bulk, are removed from the giveaway list.

Please also read the rules and faq, while you can, because i don't think you have.

For future reference if you're wondering, check this.
https://www.steamgifts.com/discussion/pJRbR/can-we-have-a-list-of-games-that-cannot-be-created-as-giveaway-unofficial-list-inside
Or any similar threads

oh didn't know it was given away. i won it at a private giveaway on a group. thanks for clearing it up.