Right mate, I'm gonna be honest....and probably brutal too, but this is terrible.....
Fear not, I recommend you read the Official Community Guide to FPSC, or "Nickydude's Guide" as some still call it. It has some great level design tips in there.......
I recommend:
*Keeping away from packing more than 3 enemies into a small room, you might be trying to make it feel intense, but it just seems too claustrophobic,
*Lighting. Dear god please use some lights, lighting can make a mediocre like
comme cette look beautiful with good placement, etc,
*Story. It's almost impossible to get pulled into a game if you have no idea why you're poppin' caps into an NPC's a**, give us a good, in-depth story that'l keep us intrigued,
*Script it up. Learn FPSC's in-built scripting system. Proper usage gives you the ability to make your game
extremely more flexible and unique,