...killing all the serfs and killing the enemy soldiers by hunger.
Yeah, this is how I have made the campaigns and other maps easy to win for myself over the years (I have been playing almost since the original game was released...off and on...sometimes I skipped playing for several years at a time). If you become a member of this forum, you can download and view my replay of mission 18 from
this post to see how it's done!

, especially that there's a bug (in the remake version r5503, the current version) in mission 18 (addressed
here). Besides my clever strategy to bypass the bug, the replay shows how I typically have starved the enemy soldiers. I find that doing this in mission 18 is much easier than mission 16, and mission 16 is easier than mission 15.
To believe it or not, you can also do something similar to this with mission 14...you just take your 6 scout, send 3 to the northeast village and 3 to the southeast village AT THE VERY BEGINNING of the game. Kill the laborers before they build a school house. You have to sacrifice your scout in order to accomplish this, but you will easily win the mission after as you will disable all threats (even your formally worthless ally will have fun destroying the enemy buildings!).
In addition, I just did the starving technique for mission 20 (today, as a matter of fact), which you can find a replay in
this post. It's very difficult to do this in mission 20 compared to other missions because the AI is a little smarter, but with a slight twist, you in effect do the same thing.
now the entire campaign is not unlocked for me, but I am sure that in the mission 18 it is possible to do the same.
You can skip missions easily if you have the remake (if I recall correctly, there was a way to easily skip missions in the original game too). I assume you have the remake (that's how you can see replays). Just go to the campaigns folder, copy TSK18 and paste it into the maps folder. Then you can play that level without having to play any preceding levels (play it from the single map section in the remake menu).