Ok well here's my thoughts, I restarted from mission 1 (had to drop all my weaps and items, but couldn't drop armor or ammo, so i had to shoot all my shells once I got my shottie and stand and get hit till all my armor was gone :-p)
The first level was pretty interesting, I got the shotgun and that came with 10 shells, after that I had to use my blaster to kill everything else, there was no ammo whatsoever.
The next level was better, there was actually (a little) more ammo and you get the machine gun as well. Killing the basic grunts is pretty easy so you don't really need to waste more than 5 bullets max on one of them, although the stronger ones do require more of an expenditure of lead.
Next came the supershottie level, which was funny because I actually got TWO supershotties from enemies before I even came to the room where it usually is, IMO that kinda defeats the purpose of going there. (Maybe just have the monsters drop more ammo other than weapons...)
By the end of the unit I was getting a little low on ammo, but still managed to pass it with quite a bit of ammo and without using any quads or invulnerabilities. Here's my equipment so far:
1 Blaster (duh
)
2 Shotgun
2 Supershotgun
1 Machinegun
181 Bullets
9 Shells
9 Rockets (Leftover from last game-can't drop ammo)
260 Cell (Ditto)
96 Slugs (Ditto)
5 Grenades
1 Quad
1 Invulnerability
1 Rebreather
1 Silencer
IMO the less ammo does make it harder, but I'd rather have seen more monsters instead (I know it'll take time to code, I'm just saying
)