Hi @pmk,
Welcome to the community 
Great to hear that you are looking to integrate Ethereum into your games. I am a huge fan of true digital ownership of digital assets using blockchain. A game first approach is a really good way to tackle this. The challenges are cost and speed of transactions, and abstracting the blockchain for users (but providing easy transparent access to blockchain information). In my previous life I worked on a blockchain gaming project.
Was it from a blog post or a video from Ivan on Tech that you heard about OpenZeppelin? (I did a quick search to see if I could find it).
I suggest having a look at the upcoming release of OpenZeppelin Contracts 3.0. The latest release candidate is: OpenZeppelin Contracts v3.0 final release candidate This has improvements for ERC721 such as automatic token URI.
You can also follow Michael and Luis on their Coding Journeys (or even share your own coding journey): https://forum.openzeppelin.com/tag/coding-journey