Nice action and indeed interoperability is important for blockchain in gaming. They were several examples that could be inspiring (historically order):
- In 2016 already 2 cards/tokens of
https://spellsofgenesis.com/ were playable in another game,
http://www.mandelduck.com/sarutobi/
- In the same ecosystem (on Counterparty/Bitcoin), several games & collections of
https://app.bookoforbs.com/ have common playable items: Spells of Genesis, Force of Will, Age of Rust, Mafia Wars, etc. even with other games like Augmentors, or in another blockchain like with Beyond the Void (on Ethereum)
- Cryptokitties.co allowed kittyhats.co and then promoted the concept with
https://www.cryptokitties.co/kittyverse
- Alto made a challenge contest for its crypto-items usable in multiple games
https://contest.alto.io/
- Enjin followed the trends with their “metaverse” initiative
- etc.
So the concept is old, but had nice feedback from players