An excellent proposition if you like the tags - and I do.
Storywise, LonaRPG presents a dark and gritty setting, where terrible things happen to otherwise normal people, corruption abounds and twisted things occur. This pairs excellently with the artstyle and sets in contrast the cute character design the artist/dev is known for with the subject matter, making for a compelling experience overall.
eccma417's art for the game is stellar and expressive, capable of conveying both the highs and lows of the characters depicted. Character and expression diversity in general is pretty damn great, with a wide range of NPCs, from the happy-go-lucky and sweet and innocent to the horrible and twisted.
Also appreciated is the scat/watersports toggle, very thoughtful and considerate. The English lines are well-contextualized and genuinely don't feel ESL or pull you out of the experience, though I will say some of the latest possible content(regarding Milo in the high-class bar in the uptown district, as well as Cecily and her retainer) remains untranslated even if language is set to English. I'm sure this will change as the game receives further updates, though.
Combat and gameplay mechanics. Combat itself is directional hack & slash, with several abilities and ways of defending yourself and affecting the outcome of encounters based off abilities slotted into action bars. It's hard but rewarding and requires you to use the environment to compensate for Lona's relative weakness compared to her enemies. Use chokepoints, use stealth, use potions and the like.
The game follows a series of quests, some of which are very lovingly detailed and thought-out, though it's notable that there is extremely little handholding. A Walkthrough isn't an absolute necessity, but it may help you derive significantly more enjoyment from the experience. I personally found the whole 'grab the quest announcement off the board' theme to be very true to the adventuring guild style storytelling you see in some eastern titles.
The game has extensive stat-tracking and condition tracking, providing a detailed record and a fair amount of information regarding Lona's current status, though you'll have to intuit what certain stats(such as Sexy or Weak) actually do. Similarly, the economy may seem quite unintuitive at first glance, but after a bit of getting used to it and the carry weight systems began to flow nicely in my experience. It's a little clunky at the start and may seem clumsy, but it gets going rather nicely as you progress.
Apart from the excellent lewds - consensual or otherwise, including several different types of prostitution, rape, slavery, parasites, monsters, etc. etc. - and the combat and itemization, perhaps the most standout thing for the game is its mood.
LonaRPG's mood is set through everything from the gloomy but warm lighting, to the choices of color for character designs, to the sketchlike art for encounters and spriting. Bright doesn't necessarily mean friendly, and dark doesn't necessarily make for a foe.
All in all, an excellent experience, with a good helping of content. Looking forward to more.