I have two nice games to recommend, however those are built on Ethereum. I can't imagine how expensive a game would be to support BTC transactions!
This RootStock sidechain seems interesting, but as far I as I was able to research there isn't any game supporting it, it's only a theory so far.
In that case, I think that the RootStock sidechain would serve its purpose well for Bitcoin-based games. LN could be used for decentralized online casinos, while RootStock would be used for other games that would make use of NFTs, and more. I would be surprised to see a game which resembles the CryptoKitties game, right on the Bitcoin blockchain (via the RootStock sidechain, of course). This would enable a whole new functionality for Bitcoin that was never thought possible.
If this becomes viral, then Bitcoin would not only become popular as a store of value, but also as a cryptocurrency for online gaming. In comparison with Ethereum, games would be much more secure and safer on Bitcoin with the use of RootStock, simply because Bitcoin has more hashpower than any other cryptocurrency to date. However, the success of this will greatly depend on how many people would adopt Bitcoin's Layer-Two solutions (LN and RootStock) for gaming.
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If you want to play something
TODAY and you don't mind touching Ethereum,
Axie Infinity (a pokemon-like collection and fighting game) and
Gods Unchained (a TCG) are some high quality games which might also earn you some money if you collect and trade rare items.
Axie Infinity is planning to support LOOM soon in order to reduce the tx fees.