So I finished this, it took me some 15 hours while doing all side quests and just taking my time exploring and hunting secrets while playing on hardest difficulty.
Combat is pretty good especially later when you have a big selection of weapons, powers and gems that allows you to mix things up a bit. Game is rather easy so playing on Insane is mandatory, getting in fights with large number of elite enemies can be quite tense and fun since a single mistake can mean your quick death.
Writing is shit and you are better off skipping it all and decreasing the volume not to hear Wangs "jokes".
Visually the game is decent with exception of character models which are rather crude. The combat effects can be overwhelming and at moments you feel like you are playing while high on acid.
Map design is quite bad, it looks like they made number small map pieces, glued them together in different order and presented each piece as a different map. Which wouldnt have been much of a problem if there was bigger diversity in environment, but as it is it just feels like a "Deja vu" the game. Not to mention that the maps are rather small and offer little in terms of exploration.
Loot system is a mix bag, loot is focused on gems that offer you to upgrade your weapons to act differently and open new tactics to approach combat. Weapons alone drop rarely and mostly youll get them from quest rewards and from stores. You will get showered by gems while playing and vast majority of them will be completely useless. Browsing your inventory to check every ones statistics can be a chore.
So in the end its a game with really good combat, especially later in game and on higher difficulty, but everything else is mediocre at best. It feels like a half of a game, like they made a good mechanics for a FPS with RPG elements but everything else was done in a hurry at the last moment.