Rhya's Crusade just released. It's a pretty fun little Contra-Like with lewd content, though there are a few ways in which it's different. RC brings the grenade mechanics from Metal Slug into the game, and unlike most run & gun games, you can select between your standard gun and your power weapon - letting you save them for more dangerous enemies or tough situations. You only get one life, and can only take three hits (which strip off your armor) before you die, but continues are infinite and you do get a checkpoint or two per level - so while it can be hard, it's not too punishing. At least I don't think it's that hard yet, but it's getting mixed reviews on Steam right now largely because people are upset that there's gameplay in their tiddy game. How dare they.
Although there is lewd content when you get defeated, the vast majority of the adult content is locked behind either finding secret areas in the levels, or from defeating bosses. So it's not like it's rewarding you for losing, and at least some of the lewd content is locked behind Normal Mode - so you're actively punished for being a huge pussy and choosing Easy mode. I suppose my biggest criticism of it so far is that there's really only one lewd scene per level featuring Rhya - while the bulk of the adult content is from the secrets you discover that you have to exit to the game's gallery to view. These don't feature the protagonist or antagonist that I've seen so far, but seem to be video logs from random rape/experiments the antagonists are committing across the galaxy. That, and you can't switch your aiming direction while crouched. Not a huge deal, but when you've found a good spot to duck incoming fire, you may end up taking a bullet or two to the face in order to stand up, change direction, and crouch again so that you can hit new incoming enemies.