In future, I suggest posting the titles of the games, and giving out the codes via private message after a day or two, to randomly chosen people who have replied to the post by then.
When they’re posted publicly like this, or given to the first responder, they tend to be grabbed by bots and resellers.
Unfortunately, that’s not effective against modern bots, since an LLM can easily solve such puzzles.
It also favors people who script notifications or spend their days on social media in order to hoard game codes, rather than giving people who would actually play the game a fair chance. I don’t know if this has become common on Lemmy yet, but it was very common on Reddit.