how do you play this game anyway it's difficult for me ?
Git Gud.
If you still want help, you start out with a combo of traps into a monster to do just enough damage to strip the chick, then use traps to slide her into monsters so they lewd the chick and move her face in the bar at the top all the way to the right and she nuts. Do that over again in different rooms with different monsters to unlock new monsters in new rooms to do it with. Most of the monsters on the map need to be summoned, they don't spawn naturally. Only the special scene monsters and the first monster on a list (except for the hydra egging) spawn. You need to use the skeletons to unlock the hydra. Everything else you have to use summon in the right room to get. The monster map (T) shows you which monster you need to get to fug her to unlock the next one, and the dungeon map (M) shows you where you are, and what monsters can be summoned in what rooms as of now. The symbols on the monster map cards represent the different characters, each one has a few of their own unique monsters. Oh, and if two monsters for the same character lead to a different monster, you've got to do both to unlock the new one. See what monster you wanna bang, look at the map to see where it is and how to get there, then go there and use the slippy boys to make them smash. If you want everything, hold off on the tit monsters until you've made her nut a few times and you've seen the unlocked special scenes, because you can't get them when the chick has blimp tits. Speaking of, some monsters (like those tit ones) will change their scene dialog depending on how many times the chick has came so far, and how many times you've seen the scene. Pretty sure some of them add more cum to the cg too. Some will change when her health gets low, so if you wanna read them all, try it at different times. Also hold off on going into the treasure room that's blocked off by a wall that you've gotta use the hole to get into, because once you leave that room you can't get back in, and it has a monster that doesn't spawn anywhere else. So make sure that there's a monster there and not the chest when you go in, or you're kinda screwed out of that one till the next playthrough. Same for the treasure, make damn sure you pick it up before you leave the room(and unlock the next monster), or you're boned.
The other goal is to go to all 3 treasure rooms, get the treasure in them, bring it all to the imp room to get the last piece, then face the boss. You'll know when you get the treasure, because there's some text saying you picked it up. The end is slightly different depending on the girl's stats. Mainly her health, and if you've changed her tits yet. The room in the very top right of the map is the best one for doing damage to her if you want to get her health to under 30%, because you can teleport her into one of the squares and usually combo the four catapults into a monster for a lot of damage, but not enough to kill her outright. Especially if you add a slime or two into the combo. Probably save first (from the system menu in the top right) so you don't have to start over if she ends up dead. Then you can do the other one. Rinse and repeat until her health is where you want it. If the catapults will kill her, but you've already cleared one, you can use the fact that she can't get out to set up just the right amount of normal traps to do smaller amounts of damage. Again, save first.
Someone also posted a map earlier that's pretty helpful. It shows the room connections that aren't obvious, like how to get into the treasure rooms. Other than that, play the tutorial, and read the instruction manual.