There's a few cvars that you can play with that could help give you that pixelated look you're after.
vt_upsampleSharpen (Defaults to 96)
vt_upsampleNoise (Defaults to 8)
and probably the main one for you 'vt_upsampleFilter' it defaults to 3 ( bicubic )
Shadows on geometry (like the floors and ceilings) are going to be a little more complicated, the original doom engine pretty much had the brightness hand set for each sector to fake shadows, it didn't really have a lighting system like Rages.
When I was working with my doom materials I found it helped to make sure 'texture detail' was enabled when I was testing to check how they looked, but I had to remember to disable it again before building (the build crashes on my machine when it's on)
You can also set the player speeds through the cvars so I wouldn't worry about the player being too slow.
But looking good so far DoomMarine, I wouldn't panic too much about the blurriness a few tweaks should sort that out /smile.png' class='bbc_emoticon' alt=':)' />