The flashlight lasts 20 seconds with full charge. The lower the battery is the longer it takes to recharge. Is while recharging from 90%->100% can be accomplished in a single second, recharging from 0%-100% can take around 25 seconds.
Players have to be extremely conservative with their flashlight usage in fast paced situations. Since the implementation of the flashlight batter, glow sticks have become preferred over med kits.
@kopimi
Its a cool idea the whole 2D3D menu thing, however i have no experience in that field. While it sounds like a really awesome addition, my primary concern would be performance and ease of access. For now the current system of displaying information to the client performs well enough in my opinion. Also i have never seen something similar (to that in deadspace or what you describe) in a FPS game.
Also to make it nice, it would require lots of fine tuning and work on the texture animations (display turning on, flickering on, being on, maybe random noise, flicking off, ect.) to pull that off. Taking in account the potential benefit, it would seem to conclude as a unnecessary addition.
The whole ambient noises that get gradually louder and foot steps get quieter. While it sounds interesting, i would question the practicality and the necessity. It provides a sort of discouragement to team kill, however i don't think it would be significant enough. You also then have to think about people who would TK on purpose just so they can hear the noises louder and enhance the feel?
3D2D: The 3D2D menu would be easy to do, just looking up the functions cam.Start3D2D() on the Wiki should give you all the info you need. It would probably take 20-30 minutes tops, there's no texture work needed. Just overriding the paint hook and giving it a transparent cyan color, maybe even a simple scanline, would really up the immersiveness of the gamemode. There's no need to use textures in this menu.
Ambient Noises: The purpose of ambient noises is purely for immersion and scare factor, not as a discouragement for team killing. The idea is that slowly as you realize your human companions are dwindling in number, you get a bit paranoid. By the time you realize you're the only living prey in a ship full of starving aliens, your head is pumping and pulsing with every heartbeat. Plus I highly doubt people would be teamkilling just so they could be deafened by a heartbeat effect.
Though, if you'd rather keep the gamemode more how it is, it's your gamemode so I understand. Would you mind if I made my own Parasite clone instead? I'd love to see a more realistic and atmospheric spinoff of Parasite.