Pretty clever little game. I like all the progression systems in the game.
Weapons level up with use, and they can gain more effects depending on the type. Epic? Primordial? Some of them can evolve and have more things going off. Also, what happens can change with casts. I have a bow that does 6 different things depending on what click I am on. Click one gives extra crit chance, click 2 does something else, click 3 adds more projectiles...and so on. There are 40 weapons for each of the 3 classes. My main is one that has 3-5 orbs that shield for a hit and give life regen. Weapons for mana regen, pure damage and damage multiplier...just a few examples.
Skills are easy to understand and there's depth to them. They also level up with use. Gear also can confer skills, of which you can have 4 on your hotbar. I play huntress (ranger), but have gloves that let me summon undead pals to help me fuck things up.
Gear can be reforged to change stats/attributes/effects and reinforced to increase those stats.. You can select stats to keep or get rid of. You can add different things to it. You can add levels to them. You have to spend farmable resources to change them, but it isn't grindy and a good system.
Serenity system lets you play how you like. Want to only push one button? You get stacks of Delighted which does various things depending on your skills. Want to have a "rotation" of two buttons? Changes serenity to tormented which gives different effects. This system was put in to make fun of games with inflexible rotations and CD's. LOL.
Attribute system also clicks for me. Different types from defense to dps to resource farming and more, each category has passive effects every 5 levels that add depth to your choices.
Endgame is a bit limited, has 3 game types for farming resources and the like. Then beat final boss, and from there a mode for sweaty gamer types to min/max their characters.
Forgot to mention that swapping around skills doesn't cost you anything other than energy spent clicking on mouse button. No resource/goldus/time penalties at all.
I am not at endgame at all yet, but it is an interesting game in terms of stat design. I could easily see ripping the mechanics out 100% and plugging it all into a game with modern graphics and it would be well received by most players of ARPG's.