This is another entry in the suburban harem genre. You play a young, unassuming man who lives in a small town with two or more of the following: a hot, doting milf, a bitchy sister type, a tomboy sister type, and/or a hot aunt type. The actual familial relationship is implied if not explicit, usually because of patreon or something. The MC will usually have an enormous penis, and his boyish charms and affable personality will woo the women around him.
Milfy Day has decent models (because they are pre-made Honey Select assets), but the game itself is quite abysmal. Progress consists of showing up at the right location at the right time. Often it feels random, because the actual triggers for when an event will begin are not apparent. Prepare to click through the various locations and hope for the best. Each love interest has a relationship score, and how it goes up isn't apparent. Do I have to spam the same dialouge choice over and over? There's no feedback. You can meet the criteria the game sets out for you and nothing happens. Character X needs a relationship of >23 points, and 2 days need to go by. Then you need to "Go Home". I have a score double that, I sleep for several days, click to the map, click on the home button. Nothing.
It sucks. Beyond that, there doesn't feel like much in the way of an overaching plot, so most of the ESL dialouge you'll end up skipping past. It's clunky to the point of being barely better than an MTL. I'd say give this one a pass.