Infiltration (LW2)
The infiltration mechanic is the method by which most, but not all, missions are launched. The system is designed to provide a balance between the assignment of your haven personnel on intel gathering, the number of troops and equipment you bring on the mission, and the danger you will encounter on the mission.
Mission Description
When describing a mission there are two relevant statistics for infiltration: base enemy activity and mission expiration. Mission expiration details when the mission will expire and the last possible moment you have to attempt the mission. Base enemy activity provides a general description of the strength of the enemy forces you will encounter when the infiltration percentage reaches 100%. Missions can be attempted at any percentage from 0% to 200% and the rewards remain the same. You will always be prompted to start or abort the mission when the mission expiration time is reached, though you may choose to start or abort the mission before if you click on the geoscape bar for the mission.
Soldiers and equipment are unavailable from the point they begin infiltration until they complete or abort the mission.
Baseline Enemy Activity
The baseline enemy activity is described by general phrases and those phrases have been described to ROUGHLY correspond to the following unit counts:
| Enemy Activity Levels | aliens |
| Extremely Light | 6-9 |
| Very Light | 10-12 |
| Light | 13-15 |
| Light-Moderate | 16-18 |
| Moderate | 19-21 |
| Moderate-Heavy | 22-24 |
| Heavy | 25-27 |
| Very Heavy | 28-30 |
| Extremely Heavy | 30-32 |
| Swarming | 33+ |
Infiltration Percentage
The rewards of a mission are the same regardless of how much infiltration you perform before starting the mission, thus reducing the mission difficulty by increasing your infiltration is a good idea. The amount of infiltration percentage you gather over time is based on another value, total infiltration, which is displayed on the squad loadout screen. This value tells you how long it will take for the infiltration percentage to reach 100%, thus you can reach more than 100% if the total time is less than the expiration time. There are many factors which can affect the total infiltration time such as soldier count, weapon types and mods, soldier perks, leader perks, and guerrilla tactics school upgrades. Additionally you can spend the intel resource at any point to increase the infiltration percentage.
Skyranger Evac Delay
Several factors affect the evac delay of the Skyranger including infiltration level. source
Base Delay
- Rookie: 1 turn
- Veteran: 3 turns
- Commander: 3 turns
- Legend: 4 turns
Squad Size
- 1-3 soldiers: -1 turn
- 4-7 soldiers: no change
- 8 soldiers: +1 turn
- 9-10 soldiers: +2 turns
- 11-12 soldiers: +3 turns
Infiltration
- 0-29%: +3 turns
- 30-59%: +2 turns
- 60-99%: +1 turn
- 100-149%: no change
- 150-189%: -1 turn
- 190-200%: -2 turns
Active Infiltrations
7 or more infiltration missions including the current mission: +1 turn.
Infiltration's Effect on Enemy Detection
At baseline 100% infiltration, enemies will have their normal detection range (the radius at which they spot you in concealment). However, their detection range will increase if infiltration is below 100% and decrease if infiltration is above 100%. Maximum detection range at 0% infiltration is 1.25 x Normal. Minimum detection range at 200% is 0.8334 x Normal (i.e., 1/6 less). The effect scales linearly. For example, at 50% Infiltration, enemy detection range gets a 1/8 bonus (half the maximum bonus of 1/4).
Strategy
The breakpoints for infiltration percentage are the following:
| 200% | 150% | 125% | 100% | 92% | 84% | 75% | 67% | 59% | 50% | 42% | 34% | 25% | 17% | 9% | 0% |
Each breakpoint below or above 100% corresponds to an increase or decrease in Enemy Activity Level, respectively. Being above a breakpoint gives you a chance to reach the next Enemy Activity Level, with the chance increasing as you approach the next breakpoint. For example, consider a mission with Very Light baseline enemy activity. Above 92% infiltration you are guaranteed to receive at worst Light enemy activity, with an increasing chance to get Very Light enemy activity as you approach 100% infiltration.
There are many more breakpoints below 100% than there are above it which means missions will quickly become more difficult at under 100% and you should try your best to reach this percentage. Similarly the difference between 150% and 200% is very small and may not be worth the squad strength cuts needed to attain 200%.