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"how can I add for example 500 characters text for game which have maximum 2-3 hours playtime," And that's exactly the point.  I've answered your question on another forum but thought I'd chime in again here.  How does your site add value that the user can't get elsewhere?  It appears that the vast majority of these games are ones that don't belong to you.  So, if I am searching for a particular game, why would Google want to show me your site rather than the site of the person who created the game? I don't say this often but I think that removing your penalty will be close to impossible.  You would have to convince Google that your site adds significant value and should be included in the search results.  And that's going to take a lot more than just adding a blurb of content to each game.