Tactical Combat Missions (Apocalypse)
Battlescape combat is initiated when X-COM Agents are deployed into the following missions:
UFO Crash Site
When Agents are send on a mission to a crashed UFO they will have to eliminate the crew of the downed craft through in order to recover craft and equipment and capture live alien speciments.
Building Search
X-COM forces will search the building for alien life forms present, whether there has been a building alert or not. The owner of the building will not be pleased if there are not aliens found or if the building takes damage from the fighting. If alien forces are present tactical fighting will begin; otherwise the examination will end the same way all unsuccessful examinations end. Finding aliens in a hostile environment will result in a tactical fight against both aliens and the building owner. (e.g. alien infested Cult of Sirius buildings)
If relationship status between X-Com and hostile organizations is already at zero percent, the worsening of relationships after unsuccessful searches has no further effect on the game.
Building Raid
An X-COM Commander has the option of engaging in raids against other organizations in Mega-Primus in order to secure additional funding from any equipment recovered after a victorious battle and/or inflict economic warfare by deliberately damaging the building.
Base Defense
Enemy forces, either alien or human, might launch retaliation missions against X-COM bases at any time with the propose of destroying the installations and killing X-COM personnel.
Alien Dimension Building
Eventually X-COM will have to take the initiative and take the fight against the aliens to their own dimension in order to secure victory on the Mega-Primus War.