Given that the username of the person who unlocked the card is on the actual image, I'm guessing that these aren't things you can just find. Must be something you can do that alerts Dave, or something that he can do to you, should he so choose.
When talking about the latest console or PC release, take a moment to consider if the game involves collecting items which grant you new abilities, exploring a variety of different rooms, or a side-scrolling view. If any of these features are evident, make sure you cite it as an example of ‘Metroidvania’ at every possible juncture.
Don’t worry if the game in question seems to only loosely conform to one or fewer of the hallmarks of Metroidvania. The person you’re talking to will probably have no idea what you mean and, in order not to appear ignorant, won’t ask for any further clarification.
If your conversational partner is familiar with Metroidvania, the chances are they will just nod knowningly in an attempt to ride on the coat-tales of your pretentiousness and bad some snob-points of their own.
In the very rare instance that you come up against a real games elitist, who tries to start up an in depth discussion on the minutae of the Metrodvania sub-genre, quickly distract them by discussing the relative merits of Sonic Adventure 2’s Chao Garden or how you think Wii Fit is the future of gaming.