For the sake of completeness, in case you happen to be bound to use you CPU's integrated "Intel HD" graphics (whatever version of Intel HD you have), you will not get happy with using OpenGL as the Intel drivers are buggy, so you have to switch to DirectX.
Switching to DirectX means that you have no access to the so called "Perfect Mode" like OpenGL users do.
Your game will look worse than it does for users with a dedicated graphics card.
CPU integrated Intel HD graphics are not designed for gaming.
Just saying...
In order to switch to DirectX, please edit your conf.ini file as follows:
[window]
ColourBits=32
DepthBits=24
StencilBits=8
[GLPROVIDER]
GL=dx8wrap.dll
[game]
TypeClouds=1
Now comes the most important section for DirectX users, "Render_DirectX".
While I don't have such thing like "recommended" settings, these are settings tested by myself, working well on an Intel Core i5-3210M laptop with Intel HD 4000 graphics:
[Render_DirectX]
TexQual=3
TexMipFilter=1
TexCompress=2
TexFlags.UseDither=0
TexFlags.UseAlpha=0
TexFlags.UseIndex=1
TexFlags.PolygonStipple=1
TexFlags.UseClampedSprites=0
TexFlags.DrawLandByTriangles=0
TexFlags.UseVertexArrays=1
TexFlags.DisableAPIExtensions=0
TexFlags.ARBMultitextureExt=1
TexFlags.TexEnvCombineExt=1
TexFlags.SecondaryColorExt=1
TexFlags.VertexArrayExt=1
TexFlags.ClipHintExt=1
TexFlags.UsePaletteExt=1
TexFlags.TexAnisotropicExt=1
TexFlags.TexCompressARBExt=1
TexFlags.TexEnvCombine4NV=1
TexFlags.TexEnvCombineDot3=1
TexFlags.DepthClampNV=1
TexFlags.SeparateSpecular=1
TexFlags.TextureShaderNV=1
HardwareShaders=0
Shadows=1
Specular=2
SpecularLight=2
DiffuseLight=2
DynamicalLights=1
MeshDetail=2
VisibilityDistance=3
Sky=2
Forest=2
LandShading=0
LandDetails=2
LandGeom=2
TexLarge=1
TexLandQual=3
TexLandLarge=1
VideoSetupId=17
Water=2
Effects=1
ForceShaders1x=0
PolygonOffsetFactor=-0.15
PolygonOffsetUnits=-3.0
Hope that helps.
Best regards - Mike