Isekai Incubus is a pretty decent, middle-of-the-road RPG smut game. It has some decent strong points, and a few big flaws that all even out to equal an average experience of its type.
The title is basically the pitch: You are a young man who dies by after being smushed by a car, and is transplanted into a fantasy universe by godlike forces. Getting run down by a car is the death of choice for the isekai genre. It's like free real estate- you don't have to characterize the protagonist or their death beyond the occurrence itself. So, that's the isekai element. The incubus part of the title contains the small twist: you're turned into a male sex demon by the very god that plopped you into this straightforward fantasy world. Your sexual characteristics are dialed to maximum: your dick is enormous, you have effectively infinite stamina, and you cum buckets (literally). Any girl you copulate with becomes your concubine.
So, turns out, your abilities and natural human decency combine to provide us with the little twist of the premise: you're the only one that seems capable of saving the world from the greater evils. The devil you know, and all that. So, as you accrue women for your harem, you also right wrongs, and make friends of foes. That's about where the game is in its development.
For the good, the writing is light-hearted and the characters distinct. The art is somewhat consistent, though the anatomy is all over the place, ranging from feasible physiques to extremely exaggerated. There's a distinct forward motion to the plot, which helps.
For the bad, and there's a few big ones- you'll want to make use of the cheat options, or even go further beyond and install a cheat plugin. There's too much emphasis on the really dull aspects of RPG Maker; the combat. Common mobs actually take a lot of effort and time to beat for a smut game. It gets grindy and repetitive fast, because it's not fun to begin with. RPGM is pretty archaic unless you spice it up, but there's none of that here.
And secondly, this is the first time in an adult RPG Maker game that it's stuck out to me either way, but good god, is the map design bad. Using the default tile set, there are multiple-screen maps you have to trek through, and backtrack through, then trek again through, back and forth, over and over. These maps are very, very blandly designed, but they are also big for this kind of game. So you can actually get lost and waste time going in circles a bit before you get to your destination. If you put down the game because of the maps, I certainly wouldn't blame you.
What would help improve the game: Rework the map/dungeons to be much more simple, or more interesting and visually distinct, screen to screen. Reduce the "challenge" of the fight (i.e. give enemies about half their normal HP pools to accelerate the rote combat), or give the enemies or attacks some flair or personality (either via bespoke assets, or sexually themed animations, or something).
Some more appropriate content would be nice as well- interacting with your concubines and harem would be good. Outfits and relationship-based stats instead of any emphasis on boring RPG Maker combat would be more interesting.
There's many worse games out there, but Insekai Incubus still has a lot of room for improvement.
