If you are using AMD GPU with Mesa, you can improve Bloodlines graphics (when running the game in Wine) by forcing anisotropic filtering.

Set environment variable R600_TEX_ANISO=16 before launching wine. In PlayOnLinux it can be done in Configure > Miscelaneous > Command to exec before running the program.

export R600_TEX_ANISO=16

Note, this applies to radeonsi driver as well as to r600.

UPDATE:

For modern AMD cards, set these:

export AMD_TEX_ANISO=16
export RADV_TEX_ANISO=16

For Vulkan scenario (like when using dxvk with the game), run set this:

export RADV_TEX_ANISO=16

You can also enable SMAA antialiasing with vkbasalt. I compared - it does reduce general jaggedness of some shapes.

Example config for vkbasalt:

effects = smaa
depthCapture = off
enableOnLaunch = True
smaaEdgeDetection = luma
smaaThreshold = 0.05
smaaMaxSearchSteps = 32
smaaMaxSearchStepsDiag = 16
smaaCornerRounding = 25

Save it in some location for example as vkbasalt.conf and load with environment variables in something that launches the game:

ENABLE_VKBASALT=1
VKBASALT_CONFIG_FILE=<path_to_your>/vkbasalt.conf