Starting this thread on website redesign forwarding ideas and things that I see currently:
Rarible fullscreen is not showing the large image file, only a larger file of the thumbnail. It’s not showing the full metadata.
Example:
https://rarible.com/token/0x9d81a91b432a09ba3f8f85c392c1da1b6f7bc839:1
Opensea:
https://opensea.io/assets/ethereum/0x9d81a91b432a09ba3f8f85c392c1da1b6f7bc839/1
Also, community marketplace does not allow fullscreen.