Life is the most import attribute. Because game will over if you do not have enough life to defeat any monsters or devils. Life will decrease when you beat monster/devil. Try to pick up less damage one. Always keep adequate number of life.
Attack determines how much damage you can cause, do not worry about the problem of not enough attack, regardless how low your attack will cause damage of at least 1 point.
Defense will reduce damage made from monster/devil. Increasing too much defense will not help you a lot, because no matter how high your defense is you will suffer damage at least 1 point.
Wait is a special attribute, The less the better. If you have wait = 40, and monster have wait = 20, then monster will hit you twice while you hit monster once. And if you have wait = 40 and monster have wait = 80, you will hit monster twice while it can hits you once. Wait will not less than 1.
Damage will be calculated automatically by the game. You just need to pick up monsters/devil cause less damage. Damage = attack - defense. if damage lower than 1point, damage will fixed to 1 point.
Key, you have only one key for each game. And there are 2 ~ 4 doors in the dungeon. Once you open one door, others will disappear. So choose the door you want to open wisely.
Coin, you can get some coin by defeating some monster, and use them in shop to buy some equipments.
Star, you can get one star each time you defeat some monster exclude boss, and upgrade your ability with stars by fairy.