UFO Incursions (Apocalypse)
Alien Craft Type and Quantity Appearing in Mega-Primus
In General
Aliens send their craft through a 'portal', called a Dimension Gate, appearing at random locations and at random times within the cityscape as time progresses. It is an invunerable device.
Alien Craft Growth Limits
UFOs are 'grown' in the Alien Dimension at the start of the week and of only a certain quantity and type dependant on the number of weeks elapsed in the game:
Maximum UFO Quantity
| Week |  |
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|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 9 | 9 | ||||||||
| 2 | 2 | 4 | 3 | 2 | ||||||
| 3 | 2 | 4 | 2 | 2 | 3 | |||||
| 4 | 1 | 2 | 1 | 1 | 2 | 2 | ||||
| 5 | 1 | 1 | 1 | 1 | 2 | |||||
| 6 | 1 | 1 | 1 | 1 | 1 | |||||
| 7 | 1 | 1 | 1 | 1 | 1 | |||||
| 8 | 1 | 1 | 1 | 1 | 1 | |||||
| 9 | 1 | 1 | ||||||||
| 10 | 1 | 1 | ||||||||
| 11 | 1 | 1 | 1 | 1 | ||||||
| 12 | 1 | 1 | ||||||||
| 13 | 1 | 1 | 1 | |||||||
| 14 | 1 | 1 | ||||||||
| 15 | 1 | |||||||||
| 16+ | 1 | 1 | 1 | 1 | ||||||
| Maximum | 15 | 15 | 6 | 6 | 6 | 6 | 6 | 6 | 4 | 2 |
Alien Mission: Schedule
At the start of each week (Monday), the aliens will develop a time-table of randomly chosen days and times within this new week. When the time-tabled slot becomes current, a style of mission will be randomly chosen dependant on importance (the percentage chance) and the number of weeks elasped in the game:
Mission Schedules
| Week | Infiltration | Search | Bombing | Overspawn Drop |
|---|---|---|---|---|
| 1-3 | 100% | 0% | 0% | 0% |
| 4 | 90% | 0% | 10% | 0% |
| 5-6 | 80% | 10% | 10% | 0% |
| 7 | 70% | 10% | 10% | 10%* |
| 8 | 50% | 20% | 10% | 20% |
| 9-11 | 40% | 20% | 20% | 20% |
| 12 | 30% | 30% | 20% | 20% |
| 13 | 30% | 20% | 30% | 20% |
| 14 | 40% | 20% | 20% | 20% |
| 15-18 | 30% | 20% | 20% | 30% |
| 19 | 20% | 20% | 30% | 30% |
| 20+ | 10% | 40% | 20% | 30% |
Once a mission is selected, the aliens will allocate the UFOs required (if available) in the Alien Dimension to immediately spawn into Mega-Primus.
Note: An Overspawn Drop for Week 7 is an error in the game since the craft needed, a Mothership, is not yet available.
Alien Missions
The alien craft will materialise from the dimension gates in sequence (all Primary craft, all Escort craft, all others) according to their selected mission. When the first craft has spawned in, the next craft due will choose a gate randomly of the three, until all are present. (A save/load between each spawn will again randomise the gate choice for the UFO due to appear next.)
The alien crafts listed in "Escort" are assigned protection duty of the "Primary" group's leader, hence, the first craft that spawned into the city is (always) the leader of all primary craft. If the leader is lost when under escort, the assigned escorts will select the 'second in command' primary craft as the new leader... until all primaries are either shot down or have escaped. If no more (viable) primary craft are present, any escorts remaining will also return to the gates. Escorts are assigned escort duty only and will not escort other designated escorts. Primary UFOs will proceed with their mission regardless if an escort is available.
Craft Selection
Any alien mission chosen in the schedule will only commence if the required UFOs are present in the Alien Dimension, that is, the mission will only start if the needed craft are available, and if not, the mission will not start and the 'time and day' mission slot is forfeited.
- eg: It is week five and a time-tabled mission slot is currently available. The game will now randomly chose a style of mission: ...infiltration! Since it is week five, the scheduled infiltration mission is 13, which needs 2xassault + 2xbombers. In the alien dimension, a large selection of only the earlier UFOs are present. There are no bombers! The infiltration selection will now move 'upwards' until the mix of UFOs present in their homeworld suits the group requirement. It has found 1xtransporter and 3xscouts. The infiltration UFO group is now valid (Mission 9/Week 3): 1xassault + 1xtransporter + 3xscouts. These UFOs will now start to spawn into Mega-Primus. If a group cannot be formed, the mission will not proceed.
UFOs in the Bombing column will attack any hostile organisation's buildings.
Infiltration
If Aliens successfully target a building (unknowingly) with an X-Com base, a Base Defence mission wil immediately commence.
Alien crafts used to insert alien lifeforms into buildings:
| Mission | Primary | Escort | Bombing | Week |
|---|---|---|---|---|
| 1 |  |  | 1 | |
| 2 | | | 1 | |
| 3 |  | 2 | ||
| 4 | |  | 2 | |
| 5 | | | 2 | |
| 6 |  | | 4 | |
| 7 |  | | 3 | |
| 8* | | 4 | ||
| 9 | | | 3 | |
| 10 | | | 3 | |
| 11 | | 4 | ||
| 12 | | | 4 | |
| 13 | |  | 5 | |
| 14 | |  | 8 | |
| 15 | | | | 8 |
| 16* |  | | 7 | |
| 17** | | | | 7 |
| 18 | | | 7 | |
| 19 |  | 8 | ||
| 20 | | | 8 |
*These fleets will never appear, as the ships required will also fulfil a higher-priority fleet.
**This fleet can appear as long as the aliens have at least one Battleship and one Escort Ship (though two Battleships will still appear in Mega-Primus). This is the result of an error in the allocation of available crafts - instead of checking whether there are two Battleships, it checks whether there is one Battleship twice.
Search
Alien crafts used to search a building for an X-Com base:
| Mission | Primary | Escort | Week |
|---|---|---|---|
| 1 | | 5 | |
| 2 | | 5 | |
| 3 | | 5 | |
| 4 | | 5 | |
| 5 | | 5 | |
| 6 | | 5 | |
| 7 | | 5 | |
| 8 | | 5 | |
| 9 | | | 7 |
| 10 | | | 8 |
- Base Assault fleets can appear from Week 5 onwards.
Important: Once an X-Com base has been located, the "Search" mission style becomes an 'X-Com Base Attack' mission style (and if they are successful by inserting aliens, will become a battlescape Base Defense mission). Any further X-Com Base Attack missions will use only one UFO; the first primary craft in the "Search" table is only used (and maybe some escorting craft) since the aliens don't need to search so many buildings now, they don't need to use so many craft!
Aliens that have located an X-Com base will cease searching for bases until their target is destroyed.
Bombing Buildings
Alien craft groups assigned for building destruction, using gun and bombs, of hostile organisations in Mega-Primus.
| Mission | Primary | Escort | Week |
|---|---|---|---|
| 1 | | 4 | |
| 2 | | | 4 |
| 3 | | 5 | |
| 4 | | | 4 |
| 5 | | | 5 |
| 6 | | 6 | |
| 7 | | | 7 |
| 8 | | 9 | |
| 9 | | 9 | |
| 10 | | 8 |
- Bombing fleets appear from Week 4 onwards.
Overspawn Drops
A mission style which always contains a Mothership as the primary leader to randomly 'unload' an Overspawn terror unit into Mega-Primus. Escort assigned craft may also attack buildings at random as with the craft listed in Bombing.
| Mission | Primary | Escort | Bombing | Week |
|---|---|---|---|---|
| 1 | | 8 | ||
| 2 | | | 8 | |
| 3 | | | | 8 |
| 4 | | | 8 | |
| 5 | | | 11 |
- Overspawn drops can appear from Week 8 onwards.
- A fleet with two Motherships is guaranteed to be on an Overspawn Drop mission.
Apcoalypse Mission
A special version of a Bombing mission which only happens once, once the Control Chamber in the alien dimension is destroyed. The next alien mission that is time-tabled wiil be the Apocalypse Mission in which all remaining UFOs in the Alien Dimension (except Probes) will swarm out of the Dimension Gates and proceed to demolish Mega-Primus!