Auto-translated
I actually saw the first two heroes for the first time only starting with this tournament.
But the thing is that all versions are quite similar to each other.
I played a lot of the 3rd game, a little of the 4th, and also gained some experience playing after the tournament for the 1st game (also played it for the first time, but the versions are very similar).
I think the key here is effort.
1st run - 18 days, managed to improve it to 16.
2nd run - 8 days.
3rd run - 7 days, but for this, I had to completely replay the map.
In the fortress, I also didn't build anything, only bought heroes:
Barbarians - movement speed + attack;
and Necromancers - gargoyles (battle speed) and centaurs (meat).
To achieve the result, I had to plan the movements of almost every hero, starting from the 1st day.
In the first 2 days of the game, the most important thing was to buy as many heroes as possible, that is, to gather the largest piles of gold, and on the 1st day, I managed to buy 4 heroes (and in total, there were 5).
It was also important to correctly divide the small army available so that it could cope with the boars and the capture of castles.
And on the last day of the game, there was still so much gold left that it allowed me to collect almost all the mercury near the castles.
The most important thing I learned from this game is that you need to break through as quickly as possible, without being afraid to lose some of your army.
Because before, I always messed up because of this (for example, in the tournament for the 1st game, I was afraid to take out the ogres).
You sit there, accumulating an army, and only to come out of the battle without any losses at all.
But this can cost you several days of the game.