Enemy Respawn Rates in Open World Games - Striking the Balance

Updated: Feb 15

S.T.A.L.K.E.R. Lost Alpha – a masterclass in enemy respawn mechanics
S.T.A.L.K.E.R. Lost Alpha – a masterclass in enemy respawn mechanics

Respawning enemies are a feature common to almost all open-world games. This is a good thing, since if the enemies didn’t respawn the world would soon be depopulated of threats and become rather boring. Games go about managing respawning enemies in several different ways. How these are implemented can result in some very different outcomes.

Respawn Mechanics - Getting it Wrong

Far Cry 2. A great game marred by poorly designed respawn mechanics
Far Cry 2. A great game marred by poorly designed respawn mechanics

Some games will respawn enemies ad hoc, i.e., if you kill two NPCs then two more will respawn. Some games, however, manage re-spawns by squads, only respawning a squad once all its members are slain.

Some games tie respawns to time - for example, enemies respawning after 24 in-game hours. Some tie it to entering maps and levels - for example respawning all enemies every time you enter a specific map. Others do it via distance from the spawn site - i.e. enemies will respawn once you have moved a set distance from their spawn site.

Tying respawns to map/level changes can cause some immersion wrecking, not to mention irritating, quirks. Imagine defeating all the enemies in a map then travelling to another for a few minutes, then returning to the original map, only to find all the enemies you spent so long defeating have respawned. I have encountered this more than once. The thoughts that went through my head were:

"Where did they all come from? How did they get here so fast? Didn’t I just kill them all five minutes ago?"

A respawn mechanic such as this might be useful for grinding XP in an RPG, (Mudcrabs anyone?) but it isn’t exactly realistic. What’s more, being forced to fight them all over again when you didn’t want to was infuriating.

Tying respawns to distance from spawn sites presents the same challenges, only magnified. One particularly egregious example of this is the respawns in Far Cry 2. I remember one occasion where the enemies respawned at a checkpoint I had just cleared when I had walked only a hundred yards or so down a road. This was thoroughly unrealistic and annoying as CENSORED. It was made worse by the fact that there are no rewards or XP to be gained in Far Cry 2 from gunning down yet more enemies. Combat in Far Cry 2 can easily end up becoming a tedious chore. What’s more, it makes the player’s actions feel insignificant, as your efforts appear to have little impact on the game world.

Basing respawns on time generally works better, so long as they are implemented correctly. If the respawn delay is too low it can feel unrealistic, annoying, and can make the player’s efforts appear pointless. If the delay is too long (say over an in-game week) it can make the map feel empty and boring. It may, however, make the player’s actions feel more impactful.

“Yes, this place is now a ghost town. You did that when you single-handedly took out all those Cybernetic AlienZombieOrcs. Well done you!"

Respawn Mechanics - S.T.A.L.K.E.R. Lost Alpha Gets it Right

Striking the right balance is a challenge, and not all games get it right. There is one game / standalone mod that strikes exactly the right balance - S.T.A.L.K.E.R. Lost Alpha Developer’s Cut 1.4007, or simply ‘Lost Alpha’ for short.

Lost Alpha Developer's Cut Release Trailer

A short video introducing the latest version of Lost Alpha, in case you have not heard of it before. It ends with the player being ‘Lost to The Zone’ at the claws of a Chimera

Video by dezowave

Lost Alpha’s campaign and side quests often involve moving between maps and back-tracking through previously explored areas. To prevent this from becoming boring, whilst ensuring the player’s actions feel impactful, Lost Alpha uses a hybrid system for respawns. It works like this;

1) Enemies at major campaign locations do not respawn at all. Therefore, clearing out a major base becomes a major story element that will affect the gameplay afterwards. This base can now be safely explored, and friendly NPCs may start camping out there. This will make the area around it safer.

2) Especially dangerous mutants, such as Pseudogiants and the terrifying Chimeras appear not to respawn either. Taking out one of these beasts thus becomes a major achievement. This can make areas that were de facto no-go-zones safe (relatively speaking) for exploration.

3) Lower tier mutants and some NPCs will respawn after a few days in various locations. Because of this, revisiting areas does not become tedious, and you will still have to keep your guard up.

Exemplar Example: S.T.A.L.K.E.R. Lost Alpha 'Darkscape' Map

S.T.A.L.K.E.R. Lost Alpha Darkscape map satellite view
S.T.A.L.K.E.R. Lost Alpha Darkscape map satellite view

Warning - spoilers ahead!

Possibly the best example of these mechanics in play is the ‘Darkscape’ level. When you first enter it as part of the main quest you are in a vehicle being chased by a Mi-24 Hind attack helicopter. Since you probably have no weapons at this stage capable of taking the Hind down your only option is to flee at breakneck speeds along the level’s twisting main road.

The military has set up ambushes for you along Darkscape too, with some troops armed with RPGs. The road thus becomes a high-speed gauntlet with no time to stop and admire the scenery. You eventually give the helicopter the slip by entering an old disused train tunnel.

The immediate threat has passed, but the military ambush positions are still in place. Taking them out will involve careful planning and stealthy movement on foot. However, a Chimera lives not far to the south, so going anywhere on foot is tantamount to suicide with that thing running around.

Therefore, the wise course of action is;

1) Set up an ambush for the Chimera so you can engage it on your terms instead of being hunted by it.

2) Once that has been completed, stealthily and methodically move north through the map engaging military NPCs and low-level mutants as you go.

3) Once this has been done the Darkscape map will become safer to explore. Your efforts in defeating the enemy are now rewarded by the loot you can scavenge in the now ‘pacified’ map.

Lower level mutants will still spawn in various locations every 24-48 hours or so, therefore the map will not be empty. There will still be things to watch out for and fight with to keep it from becoming boring.

I couldn’t find a video showing how the respawn systems work, but the early part of the video below shows the Darkscape level. The village is where the Chimera often lurks - using the buildings to your advantage is key to defeating it. Later we see a dead soldier with an RPG - one of the ambushes you will encounter.

Stalker Lost Alpha Darkscape Map

Spoiler warning - do not watch if you wish to explore Darkscape 'blind'.

Video by Evgeni Yordanov

This escape - pacify - explore gameplay loop is repeated several times throughout the game’s campaign. This gives a great feeling of accomplishment - The Zone is being made safer due to your efforts. Seeing friendly NPCs move into and explore areas they were unable to before helps reinforce this feeling. In theory, this hybrid system could be implemented in other open-world games with similar results.

S.T.A.L.K.E.R Getting it Wrong

The other games in the S.T.A.L.K.E.R. franchise can also be used as examples of how-to - and how-not-to - manage and implement respawns.

Clear Sky - the second game in the series - suffers from too-frequent respawns. This is particularly frustrating as it makes certain objectives - such as wiping out an enemy faction wholesale - impossible since its members will keep respawning ad infinitum.