Personally i would recommend looking at the CG instead of bothering with this. but if you want to anyway. my biggest gripe with this game is the need to replay to get 100% unlocked. i am not a fan off this.
anyway, the game itself is a visual novel with a grid based sections which you simply move where you want with a limit of moves per battle. the enemy doesn't do anything they just have stats which do damage to you and may take more than 1 move to kill.
it's a really simple game.
the words when selecting stages are unreadable, and there may be a few mistakes in grammar but its good quality overall.
TIPS for 100%
i think it can be done in 3 playthroughs...
1st-when you reach stage 2 lose intentionally. i mean run out of movements. this triggers a scene.
every stage make sure you use the explore map feature to look around for events (icons of the girls) except for stage 3 all are available at the start assuming you meet the requirements (enough perversion probably)
but on the 3rd stage 1 more event pops up right in the town near the end so look out for it.
assuming you did do lulus scenes there should be achoice to send her to negotiate with the beast men. sent ennoi in this 1st playthrough.
continue the game making sure you get every scene (map viewer=important)
2nd-now on the second playthough, once you get to the decision to send someone to beastmen choose lula. this is because another battle appears for some reason only if she is choosen (it is there when you would start the "south" battle.
continue until you reach the"east" battle. if i assume how the game works correctly...another location the demon king place should appear. there is 1 event in the field and 2 events tied to defeating the demon king. i think its based on who has the most perversion which will be ennoi if you found every event for both.
3.now that you got the 1st demon king cutscene...here is the 3rd pointless playthrough of picking lula to send again, and avoiding ennoi lewd events (lula needs more perversion) get to demon king, defeat him. and after a potentially boring experience. i may have all the cgs!
or just use a save data if someone kindly shared one. you still get most of the story form the scenes anyway.