If you are experiencing some graphic objects, like the grass and trees, appearing "blocky", open your video card control panel (typically named NVIDIA Control Panel or Radeon Software).
Make sure Antialiasing and Anisotropic filtering are set to "Application-controlled".
Open theHunter launcher and select "Game settings" from the settings menu in the top right corner. Set Multisample Anti-Aliasing to "1x" and Anisotropic Filtering "Off". If this clears up the blocky graphics, change Multisample Anti-Aliasing to "2x" or higher and try launching a hunt. If you make it to 8x, then do the same with Anisotropic Filtering.
Once you get the blocky trees again (or a launch error), reverse the latest change. It means you have reached the maximum performance settings for your graphics card.