I'm not very much into deckbuilders so maybe I overlook some nuances which were obvious to a frequent player of such. But this is an interesting approach. You create the story dialogue and actions through the cards. This is different than Gwent where the story is outside the card game - and it's just a card game between two people, about ressources. Here, the cards define the plot.
And, as I like a good story, was hooked into it. The writing is great. Minimalistic, precise, sufficient, fitting the mood. One can feel the world behind it, even if there's only a static image which sets the surroundings of the Trashline. Probably I had some bad decisions but at least I could met the Gatekeeper. Would have taken more time and tests to get further. But as this time I was not invested enough, because of the genre. So regarding the first question "fun and great" I liked the story and the mood more than the gameplay itself.
How retropunk it is? I find it difficult to differentiate whether the style is "normal cyberpunk under the constraints of a GameJam" and "this is typical retro compared to other cyberpunk deckbuilders" if there are many at all. I can see that it is solid but not as polished as a commercial deckbuilder made by a team. Aside from the GameJam, I wouldn't have thought that this is retro. It works, it is an Indie product, everything fine... but I would have expected the same result in another Cyberpunk Jam without the Retro Tag, As I said, only a real deckbuilder player can judge the "retroness" of this. For me, it is good, but not exceeding retro.
And does it make use of the theme? Same thoughts. The story, style, colors feel like decent but normal cyberpunk to me... so cyber yes, noir less.
And hey... you got me into playing a deckbuilder after some time!