Note that different language versions differ in their features and, important for wine, their game protection techologies. Currently the german version does not use any client-side game protection.
The game is a mixture of beat-em-up, side-scroller and CORPG. You can only walk in two directions: left and right (and jump up), but different paths if you are on the top of a platform or below make it possible to actually move not just in a plane, but in different paths in a 3D-world.
You control your character with the arrow keys and may use simple attacks (combined into combos) or skills. You fight - either alone, or, especially in later dungeons, in groups - in instanced dungeons and gain experience and items there. After leveling up, you get stronger and can distribute skill points in a skill tree. Other methods to get stronger are getting better weapons (and sets), upgrading weapons, adding stones to weapons (more attributes) and adding "eldrits". Additionally, there is some PvP.
The quests are usually consist of doing the same dungeon over and over again. You may only choose between a few "standard" dungeons at one level, but you can also do some "special" dungeons available for multiple levels adding at least a bit of variety.
The business model is F2P and thus you can buy non-advantageous costumes and different advantages (like more skill points, more skill slots, items for lowering the chance of getting the item destroyed when trying to upgrade etc.); players are encouraged to buy these advantages because of the increasing game difficulty and because these advantages can be fully exploited in PvP as well.