The game is easy to understand and play through. Each character has its own weapon and armor set. Accessories (ring and amulet) can be equipped by anyone. Currently, there are 5 tiers for each equipment (1 to 5 stars). There are 10 sets of equipment that gives specific bonus if the same set is equipped (from 2, 3, and 4 set equipment are being equipped). Some bonuses are very useful for certain character (e.g. attack damage increase for knight or warrior). Some are OK (e.g. increase max HP). However, about half are vastly useless (e.g. increase gold, skill damage, movement, etc.).
I deduct 1 star from the game is because the game is pay-to-win plus the game rigs the Gacha system. The pay-to-win is that most things cost a lot of gems (premium currency). Even though the game seems to generously give out gems everyday, it will take you forever to even get one thing they offer (4k gems for a new class that isn't that much better from what you have but rather a variety). Then fusing a 4-star equipment cost gems. Level up a passive skill which may not be that great cost gems.
The worst part is that evolving an equipment to higher star RESET and RANDOM the equipment bonus attributes! As a result, your already hard to find a good 4-star equipment with good attributes become a waste of time because those attributes would be changed. Furthermore, useless attributes (movement speed, gold gain, skill damage, malee damage reduction, range damag reduction, etc) have much higher chance to appear compare to useful attributes (increase attack, attack speed, reduce all damages, critical rate, and dodge).
The Gacha is also rigged. You have about 70% chance to get only 1 4-Star from 10-draw chest. Even worse, you get useless set (for equipment) or meat and upgrade scroll (for material) from the draw! Very rare to find useful stuff. The system doesn't give equal chance to each type of drawing. It is also not transparent (not showing the odd of drawing). It is just a double slap to your face.