The game is pretty okay for what it is. I honestly feel that Roguelikes and Hentai Games rarely mix well because the point of both, doing multiple randomized runs to try and get the one run where you can basically destroy everything with a build that breaks the game and progressing through in order to gain new H-Scenes, inherently conflicts with one another. It's probably why the least efficient way to unlock the h-scenes is through farming; beating the game unlocks everything in this one and defeat unlocks one h-scene for whatever beat one of your characters.
At the very least, the game becomes much easier when you realize the main character, due to the time loops being tied to her, doesn't get her stats reset like the other characters seem to upon death, so investing levels on her, especially when an option is a blessing that buffs another unit, will help you deal with even the more annoying bosses like the salamander one that likes to spam cooldown debuffs that can practically ruin the run due to how important active can be depending on positioning.