I'm not sure if you means need more lewd content.
the RPG-like systems may not be considered as the core point. And I'm focusing on if there are some ideas that can only be used in an Action Game.
Well, if you want it to be a porn/hentai game, then it sure need more lewdness, but for an ecchi/lewd game, feels ok as it is (I didn't minded about this at the end, I downloaded a bunch of +18 games, just looking for cool and sexual games, this hooked me for the current stuff it has and the new stuff it will have, it may not be as sexual as the others I downloaded, but sure is better than most of them gameplay-wise)
I'm fan of action, most of these games are Visual Novels with usually no skills needed to clear them (This wasn't very challenging for now, but I suppose it will get better and harder)
Devil May Cry would be an good example of Action+Upgrades, I would also like to suggest auto save (I didn't saved the first time I played), there was something else that I wanted to tell you but I totally forgot about it, I will tell you if it gets back to my mind (Or if I think about something new, good luck!)
The game controls are cool now, there is a "bug", when you jump hugging a wall, your jump is smaller (For Parkour, is the opposite), it could have some extra mobility (Dash, Air Dash, Air Dodge, Double Jump), but I think you already tought about that, those could be gameplay upgrades like the dodge. (Allows you to get to zones that you couldn't before, fight better), also, crafting items would be neat (These could be extra gathering stuff, Skills for Mining rocks, Gathering herbs, Cutting wood, this idea is inspired from Romancing Saga btw.) And now I know why it was so annoying to walk through zones, you get absolutely no rewards for killing enemies, so you just rush and dodge them to get to another area.
Btw, I remembered what I wanted to tell you when I booted the game again, this is the first time I see pixelart with "Motion Graphics", I don't feel good with it, but I may get used to.
I'm blank for hentai ideas, maybe a way to get out of enemies rapes would be cool (It could be an skill), I already cleared the four missions, I suppose is everything for now.
Well, after writting all this, I decided to take a look at the devlog, it seems that it got few neat updates :D