This is one of very few games I tend to come back to once or twice a year since it's release. I've done a few playthroughs and each one has been great.
The turn based combat is a little more engaging than your average RPGM turn-based combat and fun enough that you wont get tired of doing it over and over again over the course of the game, the variety of options in team building and abilities is also wide enough to make additional playthroughs or general grinding interesting. Once you've collected your main roster of girls though, they sort of begin to outclass any of the monsters you could give birth too and you end up just grinding 2 - 3 of the strongest kinds to help you on stages where you need fodder.
The team building system is engaging to interact with, getting new girls of different elements requires you to sacrifice a main roster character or a compatible offspring of that element in a stage to a monster that is ready to breed with. Breeding with the monster knocks the character out and leaves the monster behind creating a slight challenge to trade for a new girl for your roster, girls of the same species can then breed with monsters going forward allowing you to farm them to sell or add to your team. You equip the girls on your team with armor, weapons, and equipables that you gain from grinding or buying them from the shop to up their stats. Traditional mob grinding for xp is also fairly important but it takes a backseat compared to building the right team with the right elements and abilities.
The story is fine for what it is, the personalities of the girls and a little bit about their history is fairly fleshed out for how short the game is, you get a cutscene at the start of the game and then one after each of the 13 levels, some of them come with cg's, some of them dont. It's a pretty throwaway story at the end of the day and just does what it has to in order to progress the game.
The art of this game is 90% pixel sprites that you get for either beating entire stages or letting one of your party members get bred for a level. There are a few drawn cg's but they're just sprinkled in and not very prominent, if you want to be able to access all of the scenes with every single one of the countless girls you're pretty much waiting until the game is over and the gallery is unlocked since theres a unique breeding animation for every girl, and every monster, and you will only get 1 - 2 chances per level if you play your cards perfectly to see one of those animations. They're great, and worth sacrificing a team member you dont need to see, but you're going to miss most of them during actual gameplay.
The game only has a few bugs that I know of, and i'll only encounter them a few times per run, none of them game-breaking yet.
Very few games touch this many bases, at this level of quality for me. If you're intrigued by the art and tags this game is definitely worth playing through front to back, no questions.