I have a mouse delay bug caused by sdl on my ubuntu.
How i solved it?
edit your ~/.bashrc and write "export SDL_VIDEO_X11_DGAMOUSE=0" in it.
Now you MUST call the game by a bash shell.
if you're not sure, just type "echo $SHELL".
It fix the mouse delay bug for me.
Now i can move the mouse as speed as a rail shot, and no mouse delay :)
Nice! Good find. Maybe I can force this behavior as the default. I'll look into that. Thanks for the fix.
Btw, what version of Ubuntu are you running?