Tactical Combat Missions (Apocalypse)
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.
X-COM forces will search the building for alien life forms on player's command and regardless of reported building alerts. The search does not take place in Battlescape: It constitutes a Cityscape process which can result in a Battlescape fight on positive findings. If alien forces are present, tactical fighting will begin. Otherwise the examination will end the same way all unsuccessful examinations end. The logic of an X-Com search in the fictional social and diplomatic situation of the game is that it could have negative effect on the organization's public image, so accordingly in the game engine logic the owner of the building will not be pleased, if futile/needless searches have been conducted and no aliens found. Building damage or harm to uninvolved people during Battlescape fights also have bad effect on relationship to X-Com.
Finding aliens in a hostile environment will result in a tactical fight against both aliens and the building owner. (Most common: Alien infested Cult of Sirius buildings). Note that, if the aliens and building owner are hostile to each other, they will also fight each other as well as X-COM.
If the relationship status between X-Com and hostile organizations is already at zero percent, the applying worsening of relationships after unsuccessful searches will not go below zero and virtually have no effect on the game.
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.
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.
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.