combat movement

Difficult terrain, broadly, imposes an Athletics or Acrobatics test when attempting to cross from one zone into another (Sprinting increases the difficulty of this); failure means you stop moving.

Does it look like scene from Monty Python movie? A player moves 250m (medium range) with a sword in hand. Enemy with a gun waits about 1min (1 round) for the player to attack him, then enemy can shoot but with difficulty +1 cause of engaging.
Shouldn't the rule that player character go first be changed in this case?

That's where the Ready action (hold your action until a particular thing happens), and spending Dark Symmetry points to interrupt the action order, comes in.

Thing is, every turn-based system has elements that don't like up perfectly with reality. That's the nature of necessarily abstracting movement and time into distinct ordered slices for game purposes.

I understand that, but usually rounds are shorter like 6-10sek so you can live with that when ranged equipped enemy shoots after player has moved and attacked. With long round looks like more logic would be ranged attack go first, but You right, you can always use DS point. But we played 2 days ago and my character charged at 10 undead legionnares and necromutant while the rest o my group were shooting. Enemy waited until I performed my attack, GM didn't have so many DS points to allow all of them attack first with ranged. If you use squad rule can you use 1-2DS points for whole squad to act first? Or you must spent DS for every enemy according to page 146 seizing initiative?

Actually, the duration of rounds in Mutant Chronicles is subjective, varying entirely by the situation (p120 of the rulebook), as is the "actual size" of individual zones (that is Medium range isn't strictly 250m, because that doesn't account for how big the zones actually are or what an individual zone represents - larger zones tend to be more open and have less terrain in them to hinder movement and line of sight, smaller zones are the reverse). For the purposes of effects with durations, 1 round = 1 minute, under the assumption that if rounds are shorter, it takes more concentration to maintain them in such a frenetic environment.

With hordes and squads interrupting the action order, pay only for the leader of that group; functionally, they're the one taking the action, while everyone else just assists.

Great, that's what I've expected, to pay only for the leader, now it makes more sense. Thank you.

I borrowed some math from GURPS Spaceships and came up with the idea of Combat Scale. Nathan's already got the gist of it in his post -- the length of a combat round and the size of zones is variable. All I've done is set up 3 "pre-set" combat round lengths and zone sizes. It's strictly optional for those groups who desire something more concrete than what's in the book now. The MAIN reason I'm using it is so I can use the pre-set weapon ranges, though I may end up modifying those a bit. Shooting a pistol at 50 meters is not at all the same as shooting one at 7.

Chop a zero off those suggested distances, and you'll get numbers much more similar to other games, I find.

If I had my druthers, I'd get a little more complicated with weapon ranges, possibly harkening back to MC1/2 with the different range penalties for unaimed and aimed shots. Probably something like this:

Ignore ALL present weapon range, difficulty, attack, and scope rules. Yes, it's kind of a major re-write.

Weapon Ranges: Weapons may have the following ranges: Reach (R), Close (C), Medium (M), Long (L), Extreme (E), or a combination rating. All melee weapons are Reach (R). Handguns are R/C (this renders the Close Quarters quality superfluous). SMGs are mostly C/M. Shotguns are C. Assault rifles are mostly M, some might be M/L. Sniper rifles are M/L or L or even L/E. Etc.

Attacks made within the listed range(s) are base difficulty. Attacks made outside the listed ranges are +1 Difficulty for each step from the nearest listed range.

The base difficulty for ranged attacks at Reach and Close range is Average D1.
The base difficulty for ranged attacks at Medium range is Challenging D2.
The base difficulty for ranged attacks at Long range is Daunting D3.
The base difficulty for ranged attacks at Extreme range is Dire D4.

Aiming down the sights ("Aiming") reduces the base difficulty of all ranged attacks by 1, to a minimum of 1. You cannot Aim at targets within Reach.

Laser Sights reduce the difficulty of ranged attacks at Close or Medium range by 1, to a minimum of 1. If you Aim with a Laser Sight at a target within Close or Medium range, you instead gain 1 bonus Momentum on a successful attack.

Reflex Sights have their normal game effect (i.e. a Reroll if you Aimed).

Telescope Sights do not adjust weapon ranges directly. Instead, Aiming with a telescope sight reduces the effective range by 1 step for the vast majority of scopes or by 2 steps for extremely high quality or advanced scopes.

So, what did I just do?

I modified the system to de-couple weapon range from the base difficulty of the attack and created a reason to use the restricted action to Aim. I will probably end up redefining "close" range for purposes of my personal Combat Scale rules, but that doesn't affect people using the standard combat ranges.

Thoughts?

Some examples to show that while I changed a bunch of rules, I actually didn't change the current difficulties for ranged attacks IF you use Aim and sights/scopes appropriately.

Under the original rules, a Handgun at Medium range is a D2 attack. Under these rules, it's a D3 attack. If you have a laser sight or Aim, it's a D2 attack. If you have a laser sight AND Aim, it's a D2 attack with a bonus Momentum if you succeed.

Under the original rules, an assault rifle at Close range is a D2 attack. Under these rules, it's ALSO a D2 attack. But if you have a laser sight OR Aim, it's a D1 attack. If you have both, it's a D1 attack with a bonus momentum.

Under the original rules, an attack with a sniper rifle at Long range is D1. Under these rules, it's D3. But if you Aim, it's D2. And if you have a Telescopic Scope and Aim, it's D1. And why would you NOT have a telescopic scope on a sniper rifle and be aiming?

I'll need to go through the Talents cybernetics/weapon attachments from the Mishima, Cybertronic, and Dark Soul books to bring them into line with these modified ranged attack rules.