# What are the differences between random encounters and permanent mobile enemies?

Random Encounter:

A player has a 10% chance to encounter an enemy. while moving through a 5x5 grid.

Permanent Mobile Enemies:

There is one enemy that constantly moves through the 5x5 grid and only encounters the player when they land on the same grid. Also, both the enemy and the player cannot see each other until they meet.

Obviously, the random encounter will give better performance, but are there any benefits through implementing the second option?

The probability distribution is slightly different because your previous moves influence the probability of finding the invisible enemy - the difference probably isn't that noticeable for 5x5 areas, but is very pronounced in a small narrow 1x5 area -- you will always encounter the invisible enemy once since there's no way to bypass it, but for the "random chance in every move" strategy, you'd sometimes not encounter any enemy, or sometimes encounter more than one enemy.

• How about combing the two methods together by having a permanent enemy only sometimes spawn in an area? Would this give the exact same effect as simply random encounters? Commented Jun 23, 2018 at 18:53
• no, it will not give the exact same effect, you still have the feature "probability distribution is slightly different because your previous moves influence the probability of finding the invisible enemy". The real question is do you as a player care about the difference? Commented Jun 23, 2018 at 19:55
• If your random number generator is deterministic, a player who is trying to optimize a speedrun through the game might prefer the latter, if they can predict where the invisible enemies will all be, thereby avoiding them. Commented Jun 24, 2018 at 3:48

The second option gives you a deterministic number of opponents the player will face (within a range); as in 0-1 in your case. In the case of Random Encounters, one player may hit as many as 5 if you don't cap it; while they would likely have a smaller chance of hitting 0.

The main benefits I can see is it allows you to:

• Have cool items that maybe temporarily reveal where the thing was or is, giving depth of gameplay

• It can be used on particularly tough opponents, encouraging the player to find those items, but they don't have to. This allows the player to make a meaningful decision: "Should I search for items X or Y or should I gear up for a massive fight?"

• Having it "hunt" the player a bit, maybe the player "makes noise" when they move or similar, allowing further depth of gameplay where moving slower, skirting the edge, etc. allows you to dodge it with better; possibly with a "throwing rocks" mechanic that Far Cry and similar games had

I can't think of anything outside of these types of mind-games and decisions that it allow. Remember that Games are a 'Series of Interesting Decisions', so when implementing a thing; see if it affects the gameplay in a way that affects decision making. If not, you can consider removing it; simplifying it; or adding decision making to make it more interesting.

The above Lures, Monster-Finders, etc.. may all be single use things; allowing you to skip one of a number of fights; making which ones you do meaningful. Additionally, being "hunted" and having things assist you with that adds a lot of atmosphere, where random encounters are just there for grinding and simplification of development.

Supplementing Jimmy's answers which I agree with.

Benefits of random encounters:

• Better control of the number of encounter per time unit.
• Invisible process, so it may be tweaked dynamically without the player noticing (e.g. you may put a cap on the number of encounters per area or automatically trigger an encounter after a certain amount of time if none had occurred).
• It can also be tweaked to reflect the difficulty of the game or an area with only one parameter.

Drawbacks of random encounters:

• It feels... random ;) If your game is not about grinding, it may feel like random encounter interrupt the flow of gameplay or the player's plans.
• If you don't supervise the randomness as suggested above, can create very unbalanced experiences (too few or too many encounters).

Benefits of mobile enemies:

• Encounters can be anticipated and even avoided if the terrain lets the player move around them. It's a great way to give the player a sense of control, even if they find an enemy in a corridor (they have the time to craft items, review the characters, save, etc.).
• You can have a visual representation of difficulty: an area crawling with encounters, a lone enemy that can be avoided but looks XP/loot-worthy, etc.
• You can add gameplay to the map level. Maybe the different enemies have different speeds, movement behaviors (chasing, defending a place, flocking, etc.), movement capacities (flying, crossing water, etc.). Maybe the player can affect the enemies' behaviors on the map: dropping an object that lures them or using a capacity that repels them; creating barriers (fire, magic); summoning or dispelling enemies; etc.

Drawbacks of mobile enemies:

• It's a lot of work, both in terms of assets and programming. Make sure that it's worth your efforts for the player.
• It'll be harder to scale difficulty and forced encounters can feel like railroading.