Welcome to another EU4 Development Diary. We did not have one last week, as Besuchov, King and I were in Iceland showing our games to the press, and drinking beer.
Now it’s time to focus on the changes we’ve made to land combat. There will be a lot of fighting and many countries won’t go fifty years without beating on their neighbors, so it’s important to know what is different.
First of all, battles in EU3 were not really fun enough, for us. You either ran into ping-pong situations, chasing an army you could not destroy from one province to the next, or the war was decided in one battle which meant a lot of idle shifting armies from city to city.
We wanted to get a better flow of war, and, importantly, could get decisive battles that gave you strategic advantages to be able to siege down territory you want. Over a long period of testing and experimentation, we think we have now balanced combat to be both fun and plausible.
Shattering of Armies
First of all, armies can shatter. If they lose a battle while having low enough morale to be disorganized, they will be forced to retreat to a safer province much further away than just one over – it could be two or three provinces from where the battle was fought. They will usually retreat to one with a high base tax value, forts, and no adjacent enemies. While retreating, the army moves slightly faster, so it will not be overrun, and it has a chance of recovery.
What this means is that if you crush but don’t destroy an enemy army, you still have a period where you can maneuver and besiege provinces, positioning your main army to be ready, in case your enemy does recover. Of course, there is always the possibility of catching shattered armies and eliminating them, but that requires some skillful maneuvering, as well as numerical superiority and some good fortune.
Even if you win a battle, your army may become disorganized. A unit that has its morale drop below a certain threshold is flagged as disorganized, which is indicated by a small flame next to its morale bar on the map and interface. A disorganized army is unable to start moving until its morale has recovered to a certain point. With the much slower recovery of morale in EU4, this means that an army may be stuck in a province for a while before being able to continue if there was a close enough battle.
EU3 introduced a complex combat simulation with over sixty different positions for units at each side, which possibilities of units moving about and firing at their flanks, and covering holes in the line, and for reserves to enter the combat. The combat system was not as transparent to the player though, and there are actually quite a lot of the players who think its about just numbers, modifiers and dice-rolls. We have now made the interface more obvious, you can now see which regiment is fighting which, and who is moving where.
All combats in EU3 had the same possible max-width. This is no longer the case in EU4. Now you start with a much lower base combat width, which increases as you advance in military technology, allowing you to use more soldiers effectively at once. Terrain impacts the width of combat rather dramatically, so a small army can hold up a large one if they get lucky and catch them in the mountains.
In EU3, infantry could attack units in front of them, and directly to their sides, while cavalry had larger range. Now this has been expanded: a unit’s effective range depends on how many troops there are in that regiment. If you have 75% or more troops, you fight at full range, if between 50 and 75%, you fight at 50% maneuver range, and between 25% and 50% strength you can do 25% of your maneuver. This is always rounded down, so a regular infantry either have 0 or 1 range possible. However, there are technologies which increase your units’ range as the game progresses.
Supply Limits & Attrition
We have slightly increased the supply limits, and making the difference between safe and hostile territory not as drastic as in early Europa Universalis games. This makes it more possible to fight offensive wars without losing 90% of your army to attrition. Speaking of attrition, we also made a very important change to this central mechanic. Previously, if you were 2,000 men above a province’s supply limit, you gained 2% attrition no matter the size of your stack. Now the attrition you suffer depends on the size of your army compared to supply limit. You get 10% attrition if you have double the supply limit, 20% attrition if you got triple it, etc.
Manpower is now a more precious resource, but with the other changes we have made, not necessarily prone to a total collapse. Once you’ve exhausted your manpower pool, it takes about ten years to recover fully, unless you have ideas that increase this recovery rate. Earlier in the game, you may find it useful to rely on large mercenary armies to preserve your manpower, since a destructive early war could leave you at the mercy of predatory neighbors.
Armies are now slightly slower to reinforce, and reinforcement in foreign territory more greatly depends on the maneuver rating of an attached leader. This together with different supply limits means that armies will not be drained as much of manpower.
Maintenance Cost Increases
BUT, reinforcing your armies as they take casualties from combat and attrition is now extremely costly. Every unit at war that needs to reinforce will cost you double the normal maintenance on top of everything else. This means that when you are at war, and you are fighting a lot of deadly battles, you run the risk of severe debt unless you keep a huge warchest. The hope is that this will give players an incentive to keep some wars more limited in scope, increase the utility of loans for the player and raise the specter of bankruptcy, a threat to many nations that overtaxed themselves militarily.
We have tested this for months now in both singleplayer and multiplayer, and we feel extremely happy with the results, and this is probably the best combat and war system we've done, yet.
And enjoy the Europa Universalis IV: World Map Trailer!