Now that i can "read" your map design i can gove you some comments on it:
1) The map is to much straightened out to my liking. I prefer forkings and alternative routes so the player can "choose" his way to a certain extent, giving him the illusion of free movement.
2)Confronting the player with 3 enemies on the opposite side of a room without a cover is as well much to obvious and overpowering. Combat is the main action in an fps scenario so try to set up situations more challenging and rewarding, like ambush, crossfire, one on one. Simply throwing me into a room with thre badies is like a shooting range.
3)3 enemies on one segment in front of a door, wow, that calls for an Indiana-Jones-3-in-a-row shot.
4)i killed 3 enemies to free the door just to get ambushed by 2 guys attacking me simultaniously from my left and right? your player will hate you for that one. After combat there must be: ammo, health, reward- and some time to breathe through. a freed door is nice but not if it leads to instant death.
Let the player battle the 3 doormen and then find a better gun for example. and after two or three short corridoors and rooms he'll face a boss that he just wouldn't have taken out without that new toy. Now include an alternative and more obvious way to the boss without having to pass the doormen, and you will have better gameplay:
The player will try to avoid the doormen just to get killed by the mighty boss (let him mock on the players "stick weapon" with audio).
In the next try, the player will take on the doormen and have his reward.
these are just some of my personal thougths to maybe help you improve your level design. Excuse me when i went over the top sometimes.
I am Jacks complete lack of surprise.
