I need to start with this: Don't avoid because of RPG maker as the engine, its still a great game.
Tldr; Translation is great, MC known as Melty is fun, storyline is decent enough, good as an RPG on its own, and the sex scenes are fantastic.
Why would I rate a rpg makger game 5 stars, well I will tell you point by point.
Translation: Translations make or break a game, and Melty's quest has some poor wording choice here or there, the game never has outright wrong info, clear consistant mistakes, and overall carries out well.
Main character: Melty is fun, she is basically the MC of "My first girlfriend is a gal" in terms of speech and overall view on life. She has different reactions for how the world changes depending on her slut level, and her personality works in all scenarios. She never breaks the tone of the game, even in the worst scenarios, and I appreciate that.
Story: For the most part, generic story. I can deal with that, and the surprise is cliche... but the way they tell that story, the setup, actually was done really well. At first I thought it was some translation errors, or some old storyline that wasn't revised, but some of the conflicting stories all tie together to make a decent enough story on its own.
Sex: 10/10, has some stuff I am not into, but you can actually sort of stay at you're own comfort level if you want (sign of a good game) and someone might like it, so critically it wasn't a deal breaker as a straight guy (aka no scat, guro, gay, or loli) and I think most can agree with that. They did a great job on the variety, the tone, none of it was the same sort of re-hashing, overall it is higher end for this genre of games.
Newgame+ : Always add a star to any rpg that has it (fucking never understood why not).
Virgin run: I like to also give a shoutout to the fact that you can beat this game as a virgin, and the storyline doesn't seem like it was a virgin run shoved into a normally hardcore ending.
Overall, this is a great game to check out, it respected my time when I wanted it to, and has some of the best scenes I have seen in some time.