Hi! Long time HOMM3 player, first time trying HOMM2. Of the things I bumped across that are some kind strange from someone coming from HOMM3; like not being able to split a stack of creatures into two, the abscence of the 'wait' button during combat, and not being able to see what day of the week i am during a turn (only when the turn begins you can see but during long turns i keep forgeting the day) seriously is there a way to check this other than memorizing at the beggining of a turn?
But anyway, these things are ok, just need time to feel comfortable with. But one thing really annoyed me. Some creatures with AVERAGE SPEED, during combat, could cross the entire field and hit my units on 1st turn, while my ultra fast champions couldn't. How does this work? I noticed that one time while I was being under attack my champions could hit one unit that was directly in front of him all the way across the battlefield. Is this some kind of "boost to speed for whom is being under attack?" I don't get it. Someone can please explain to me? I'd appreciate. Thanks.

You can split creature stacks by selecting a stack, holding down the Shift key, and then clicking on an empty space. You'll then be asked to type in how many creatures you want to split from the original stack.

On the Adventure Map, locate the "status window" in the lower-right corner. This window will display either a hero's army (if a hero is selected) or your total resources (if a town is selected). Clicking on this window repeatedly will eventually show the Month/Week/Day. Are you sure the first round had ended, and were the Average-speed creatures flyers or boosted by spells/morale? If you can explain what happened in greater detail, I might be able to understand better.

Fliers, like fairies, can move to any square regardless of speed.

Thanks for the tips, I'll try tomorrow.
And answering both you and ZFR: Yes, after some research here in the forum i found that fliers can move anywhere, and they were Dragons, Gargoyles and Sprites. But that doesn't explain why my champions who usually can't reach the other side of the field in one move, was able to do so once when I was on the "defensive side" of the field. (it wasn't a siege, only a normal battle where the AI took the iniciative)
Also, just remebered. In this case of my champions, the shadow that shows the movement extinguished itself 2-3 hexes away from the opponent creature, but for some reason the mouse cursor showed the 'little man running' at those hexes and the sword at the hex adjacent to the unit, so I was able to strike him even with the shadow not showing that was possible.

I usually play with the combat shadows disabled, so I'm probably not the best person to ask. But I'm wondering: was the enemy creature 2 hexes in length?

Let's say you begin combat with your Champions (which are 2 hexes) on the left and enemy Wolves directly across from them. Let's also assume that there's no terrain obstacles blocking them. By virtue of your Champions being Ultra Fast, your Champions can cross the battlefield and attack the Wolves (without needing the Haste spell). If, however, the enemy Wolves (2 hexes) were replaced with Trolls (1 hex), your Champions wouldn't be able to reach them in one turn. This'll make much more sense once you understand how the various speeds (Average, Fast, Very Fast, etc) translate into grid tiles.

Alright, I've just hopped into the game and figured out what happened. You actually can go 1 hexagonal further than what is shown by the combat shadows. Don't know if this is only because champions are double-hexes units or if it's applicable to any unit, i literally just spent 2 minutes in the game and then close haha. So yeah, there are 7 grid hexes between two double-hexes creatures in a straight line (11 grids in total), and I was thinking my champions could only move 6 the entire game.
I can see now why you play with the shadows disabled hahaha.
Alright, sorry for the misleads.

For 1-hex creatures, what you see is what you get when mousing over terrain. The creature will stop in whichever hex you click.

2-hex creatures, obviously, take up two hexes. When clicking, you are selecting which hex the creature's back half will occupy when it stops moving. This is important when trying to place your 2-hexers for blocking enemies or being out of reach of enemies, etc. It also means you can't move a 2-hex creature exactly one hex in the direction they are facing unless they can also attack an enemy from that new location (the game assumes you want to click on the creature itself).

Some other notes:
-There is no 'Wait' command. Every creature takes its turn or skips its turn.
-The Slow spell will 'clip' a flyer's wings, limiting their move distance to their actual (slowed) speed. They can still fly over obstacles within their speed, but they can't just fly across the map while slowed.