Unholy Angel: Wedding Adventures starts off promising... unfortunately (and lets start of with the bad), the narrative setup in the intro is confusing. It starts off with Diana being conservative, and then wanting to explore, but then not really exploring. The intro could use some more expounding upon her college sex life before meeting her fiance. The intro sort of took the wind out of your own sails. I wanted to see Diana getting fucked in all sorts of different scenarios before meeting her fiance.
Also, there isn't a lot of deviation in the art, or showcasing of any real sex-scenes. It is just the same static image of Diana, standing in the same position, but with a change of clothes here and there and in different locations. When she was watching porn with her husband, that would've been a great time to show them sitting on the couch, fooling around or something; rather than them just standing in the same position the entire time.
The good - The premise setup is really great, and this game has a lot of promise if you fix some stuff. The intro narrative started out exciting, seeing as how you introduced Diane's step-dad, and some college flings. But you can empower your intro by actually showing Diana doing stuff with them.
Your story seems like it is going to be strong, but, first and foremost, find someone who can edit your text for you, especially for the intro.
The art (or at least the bare-minimal amount you have so far) is pretty-good, but lacks variety. It's obvious it is just preexisting images of porn stars, that are "painted" over, but there needs to be more of it. I'd imagine if you bump up the art count, and enhance the scenarios a little more, this is one of those VNs to rival Good Girl Gone Bad.
There is a TON of potential you have here, unfortunately, in summary, fix your text, bump up that art count, and be consistent with your story and narrative.