Reached around level 180 in about 3 hours

Don't give up just by looking at the level, you should definitely try it!! Click the auto button on the right!! If you click the mission on the left that says (Main) or something and set it to auto-hunt, it seems like you level up well. Also, when you reach the level where you can enter the mine, if you go to the mine, mine iron and gold ore, fight, etc., it seems to give a lot of experience. I don't know anything about games like this, but this is just my guess..? A personal experience? A feeling? lolololol If even I, who knows nothing, succeeded in getting a hidden in 3 hours, it means it's really easy, so you should definitely do it!!! For the coin gacha, I got one 100 coin and four 2000 gems ㅠㅠ That's a bit disappointing.