In no particular order:

• Game is TERRIBLY optimised - recources wasted on multi polygon architecture and some horrible shaders and other effects that dont do anything except wasting computers recources. 
• Skills are unresponsive and clunky, targeting buggy.
• Overall UI looks really bad and lowres. Minimap buttons are hard to see and have to zoom map out at the start of every level.
• Crafting doesnt work (cant collect colmpleted items). Salvage all (by colour) makes you salvae your favourite gear aswell - since there is no way to "lock" the items youre using (make them not autosalvage). 
• Button to salvage individual item is on the opposite side of the screen, so you have to drag cursor there and back to item if you want to salvage just a few items.
• Finding a mission with mobs relevant to your daily quest is a pain since you have to zoom in to every single mission to see what kind of mobs inhabit it.
• Overall gameplay is clunky, slow and unresponsive.
• Levels are to bright and visibility reaches way to far - needs a darker atmosphere with limited visibility (darkness iluminated by a few lightsources on the walls and your characters light)
• Map player indicator (the little arrow) is barely visible, and the map needs an option to be stationary (not rotate).
• Large enemies like dreds return to their originar spawns and regenerate health when kited just a bit.
• Boltgun sounds are terrible - really weak and thin.
• The starmap for selecting missions needs to be more clear and have some sort of summary of available mision types and enemies inhabiting them