Maybe it's the sourceport, but with strafing being faster than forward/backwards, the moving momentum and lack of flat surfaces making movement feel like ice-skating, weird sensitivity and acceleration (I had it all the way down and edit the inis to get raw input sorta working), confusing movement options (classic doesn't feel all that classic) and low frame animation on the enemies (deliberate, but in combination with the above...) I can't play for long without getting severe motion sickness. Autoexec kinda works to adjust movespeed, but some accessibility options would be nice :')

It's weird because the original Quake engine (and even the older sourceports) have none of these quirks.