The game is old with no update for 2 years already. It is just for your passing time.
There are 2 hero classes - warrior and mage. Warrior has skills to empower himself, perfect shield block (no damage), and damage dealing skills. It is easy to play warrior once you upgrade the empower skill length to 5 which will make the skill becoming infinite enable time length. Shield block skill is extremely good once you get the number per use increased to 5.
Mage has summon golems as his defend skill. The highest number per summon is 3. Sadly golems are weak and are used as distraction only. The good skill is frozen skill which deals on all mobs and freezes them for quite a while. This class requires a lot more attention while playing.
There are 3 difficulties - Normal, Hard, and Hell. Each difficulty has 4 stages except the last one has the 5th stage. The stage is special because both heroes will be in the fight but you can control only the one you selected. The stats from the other hero will be the same as whatever you have built.
After you beat all stages, there is nothing else you can do. The game, however, is in Japanese. No translation so it could be a problem for those who don’t know enough Japanese to play this game.