The Dark Forces may be the best first-person action video game, but it gets Marred by MOS.  It was too easy to kill myself in MOS simply by force jumping.  I died a hundred times because there was something overhead when  I jumped.  Once I died because I jumped straight up, but took damage from  the fall.  Another time I was on this ledge and couldn't get back up--every  time I jumped, I would bounce off the wall and die.  When I went to several  web sites to get help on how to get off that ledge, the best that I could  find was 'it is tricky' to get off the ledge.  After dying several hundred  times I got bored and quit.  I've never gone back.