When I first started creating these games, they were traditional I-GO-U-GO designs: one side takes its entire turn—moving units, attacking, finishing all actions—before handing control to the other player to do the same. It’s straightforward and easy to follow, but it has an inevitable drawback: the other side is frozen in time while you’re acting.

Then I thought: “Wouldn’t it be neat if it was WEGO instead?”

For those unfamiliar, in a WEGO system both players issue their orders during the planning phase, and then the game executes them simultaneously in a resolution phase—like watching a film of the turn play out.

I still think WEGO is neat—but I quickly learned why more games don’t use it. In effect, you’re making two games instead of one. The first “game” is just like IGOUGO: players give orders as usual. The second “game” is the complex job of meshing both sides’ orders together into one unfolding sequence, while handling, for example, these sorts of interactions:

- Collisions between moving units, whether delays caused by congestion or due to enemy action.

- Chain reactions—like when Unit A attacks Unit B, but Unit B was ordered to attack Unit C, and Unit C was already on its way somewhere else.

- Ad-Hoc battles - battles that are not planned by either player but occur when units with Move And Attack orders bump into enemy units when moving - this can either result in a battle or in an Overrun.

All of these require the system to intelligently resolve timing, priority, and the fog of war—without breaking the flow or fairness. And it also has to take into account movement that the player hasn’t directly ordered, like recon unit withdrawals, retreats etc.

So in this diary, I’ll walk you through how our WEGO simultaneous play system actually works, and the problem-solving that makes it tick.

So what actually happens?

Once both players have locked in their orders, the game records two full sets of Commands — every move, every attack, every recon mission, the lot.

We start by setting the battlefield:

- All units are placed in their starting positions.

- Any pontoon bridge is removed if its engineer is on the move.

- Units with breakdown/combine orders (splitting a regiment into battalions, or merging battalions into a regiment) are updated.

- Air recon and interdiction missions are assigned.

Then the scouts get busy. Ground reconnaissance units try to pull back from enemy contact — whether that’s from an ongoing battle or an enemy Zone of Control (ZOC). This happens before any fighting starts. If a recce unit has Hold No Retreat orders, it stays put; otherwise, it withdraws to a safe adjacent hex outside enemy ZOC.

Now, the real action begins: battles.

There are several types, but the most important is the Set-Piece (Deliberate) attack — carefully planned engagements that happen before any movement (other than the recce pull-backs).

Battles resolve in odds order, starting with the highest odds first.

If a battle involves air support, we may need to run an Anti-Aircraft (AA) battle first. If the AA fire forces the planes to abort, the main battle is affected — and if the fight was air-to-ground only, it might be cancelled entirely.

Once any AA step is done, the main battle (ground, bombardment, or both) plays out.

Here’s what we check after battle resolution:

- Retreat — Defenders might pull back. This is less likely if they have Hold At All Costs orders (but they’ll take heavier losses if they stay).

- Withdraw — If defenders have Withdraw orders, they leave the hex with fewer casualties.

- Units that retreat or withdraw skip any movement they’d been ordered to do.

- If a unit stays and the battle odds are greater than 1:1, it loses half its movement points (less time left in the turn to move). If odds are less than 1:1, it keeps full movement — to prevent “cheap” attacks just to slow the enemy.

- If the defender is eliminated, retreats, or withdraws, the attacker may advance into the hex.

Because battles can change the makeup of later fights, we then update the remaining combat list:

- Remove or modify battles where the defender was wiped out and was the only attacker in another engagement.

- Remove or modify battles where all attackers have already retreated/withdrawn.

- Keep in mind: if only some attackers retreat, the odds can shift dramatically.

Once that’s all cleaned up, we recalculate odds, pick the new highest-odds battle, and resolve again.

Now it’s time for movement.

The goal here is to make movement feel realistic — a unit’s speed is based on its movement points, and slower units don’t magically arrive at their destination earlier in the turn than faster ones.

For example: if one unit has 20 movement points and another has only 4, they’ll still both arrive at their destinations at the end of the move phase. We do this by dividing the turn into “movement slices.” In this example, the turn gets 20 slices:

- The faster unit moves 1 MP per slice.

- The slower unit moves only once every 5th slice.

Result: both finish at the same time on the 20th slice.

The process works like this:

Find the fastest unit — its movement points set the number of slices for the turn.

Recce pull-backs — any recon unit without Hold At All Costs or Move To Attack orders tries to withdraw from enemy ZOC. This check repeats every slice, since the enemy’s position changes constantly.

Wait orders — some units delay their movement until their wait timer runs out.

Command & Control delay — HQ inefficiency can also hold units up.

Units move — moving strips them of any dug-in bonus.

Recce caution — recon units avoid advancing into enemy ZOC unless ordered to Move To Attack.

Road movement ambushes — if a road-moving unit approaches the enemy, an ambush battle triggers (except for artillery, which doesn’t ambush). The ambushed unit loses all remaining MPs.

Move-to-attack clashes — if a moving unit enters an enemy hex, one of two things happens:

Meeting Engagement — both sides are moving; terrain is ignored and unit quality differences are doubled.

Move Battle — only one side is moving; it’s like a normal battle but with one level lower intensity.

Blocking & stacking — if a destination hex is full, the unit waits until it clears, losing some MPs while stuck in traffic.

Engineering & fortification — units attempt to breach minefields, repair or destroy bridges, clear damage, build pontoons, and dig in.

Fort/depot destruction — units ending their turn in enemy forts or depots automatically destroy them.

Readiness updates — unit readiness adjusts, reduced if they were attacked.

Supply updates — movement triggers a recalculation of supply lines, unit supply states (isolated, encircled, extended, or fully supplied), and the impact of counter-air, interdiction, and ground asset missions.

And finally… You get to sit back and watch the replay film.

I’ve actually simplified a few bits here — but hopefully this gives you a good peek at the clockwork ticking away under the hood!

WEGO WORLD WAR II: OVERLORD IS COMING ON FEBRUARY 26TH

https://testx-steam.c5game.com/steamstore/app/3639330/WEGO_World_War_II_Overlord/?beta=0