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I don't know if it's allowed to post links according to the forum rules, but if you search for "heroes 3 first blood tournament," you'll find the first or second link.
There's a video showing movement on the map (it's fantastically cool), but there are no actual battles. You can see how a hero with one angel runs and defeats 28 crossbowmen... There are many complex battles, both against monsters and heroes, but at least you can understand the tactics. I repeat - the battle, according to the tournament rules, is reproducible.
Added after 1 minute:
Version 2.5 appeared after this playthrough, and as the author writes, "the loopholes were closed."