Really really late, but here are two charts showing the damage of most of the weapons in Commando 2 as well as the health of most enemies encountered. This numbers are based on the assumption that the Barreti does a single point of damage (1). Data is gathered by playthrough, using the score as a counter, and a lot of restarting. As there was no reading into the actual game code, the following charts are subject to human error but are overall reasonably accurate.
Each number is damage per hit, if a weapon fires multiple times per shot, the number will be listed as multiplied times the amount of projectiles.
Enemies listed by least to most health on each level on easy, except on the rocket where it's listed from appearance.
Couple of notes- A few enemies do not increase in health with difficulty: all of the crates, the gate on missions 1, 5, and 9; the fruits, and the giant missile truck in missions 4, 8 and 12. There are probably a couple more, but they are likely non-vital.
Also the first destructible building in encountered Missions 2, 6, and 10 seems to have double the health as all the others.
Confirmation of the data by other players would be appreciated, it took some kind of effort to get all this so fatigue might have compromised some information.