While playing around with the shareware version 1.0, I've noticed that it doesn't handle difficulty level selection from the command line. The help says that valid skill level values are 0-3:
However, when trying to load the Come Get Some difficulty with the /s2 switch, I noticed that it would get me on a lower difficulty level instead. Using /s3 didn't help either.
I decided to investigate this, and it turns out that the difficulty levels loaded with the /s switch work as follows:
/s2 selects skill level 1
/s3 selects skill level 2
/s4 selects skill level 3
/s5 selects skill level 4
Now the fun part is, other values also load various skill levels - at least, the save/load screens indicate different values.
/s1, as you may have guessed, selects skill level 0:
As far as I can tell, it's identical to Piece of Cake.
Further on, /s0 selects skill level 255:
You can go even further by using negative values, e.g. /s-1 will result in skill level 254:
This works in the opposite direction too, /s6 selects skill level 5:
All skill levels above 4 seem to be fully identical to skill level 3.
You can also use the /q switch to turn on the "fake multiplayer" mode but v1.0 doesn't have any bot AI (as is mentioned in the supplied manual BTW). IIRC, the shareware v1.3d has a functional botmatch option but I'm not 100% sure about that.
On a somewhat related note, the early shareware versions of
Shadow Warrior allow to load a similar "Single-player Comm-Bat mode" (yeah, apparently it was called the Comm-Bat mode initially, like in
Rise of the Triad) but I don't remember if there are actually any bots there (
Shadow Warrior shareware v1.0 and v1.1 don't run in DOSBox BTW, or at least I haven't figured out how to pull that off).