Shadowed World mod for Serious Sam: The Second Encounter

So I have discussed much of a 'brief' back-story but one question remains...
What new features will this mod have? First off I have to say that this story is something I have been building to since ten years ago and this project would be my baby. I'm doing what I can to get it off the ground and then I will open positions for promising development.

• As stated in the summary, there are two factions at war with each other. I like both factions a whole lot because one reflects my 'light side' and one reflects my 'dark side' and I wouldn't want to force the player to play it one time and be like "Yeah, blah blah blah I kicked the bad guys ass." in general saying but I'd like to give the opportunity to pick between three story-lines which will of course add to the development time and make it more complex.

• Other than that I would like to add more complexity to the game play alone by adding several challenges that must be overcome by using certain weapons or being stealthy. In an example I plan on giving every weapon a secondary firing mode; and when you come across weapons much like the revealed Railgun, you will have a choice in firing modes between the standard shot or an EMP burst. Thus making some challenges where this EMP burst is necessary for achieving. (If you don't know what EMP is, it's "Electro-Magnetic Pulse"... It fries unprotected electronics.)

• This will of course be featured for Single-Player and Co-op but I wish to provide a death match game play on online and network gaming also. Also I'll include that I will provide plenty of slaughter on a couple of the storyline maps because that's why some of us still like Serious Sam; one man versus and army, although I will provide some strategies so it doesn't seem like you're lucky or just some exquisite piece of technology.

Weapons that have been discussed:
Maul (Standard swing : Shock wave attack)
Railgun (Standard Railgun shot : EMP burst)

Weapons that are in discussion: (Voting is very much appreciated on these, you vote and ideas count)
Remote Detonator
Chemical Streamer (Corrosive chemicals to disintegrate your target)
Tesla Cannon (Of course named after Nikola Tesla for the electric arc)
Sonic Cannon (Sound used as a shock wave)
Death Ray (The origin of this idea is from an ultrasonic experiment I learned about not too long ago)