Very much map dependent of course, youāve mostly covered the consistent details. Only addition is that most every map makes it clear the colonists made a concentrated effort to hold out, but were under equipped to do so and largely wiped out, so the xenos did not wipe out the colony instantly given there was time to throw up (very shoddy) barricades and form armed groups. In some cases, itās implied they did pretty well, and/or that some of the actual player survivors were what was left from those holdouts. Anyways, hereās what I noted from glancing over the web maps out of curiosity:
On LV-624, the crashed shuttle on the beach implies the xenos were unleashed onto the colony abruptly from the shuttle itself given thereās still some in stasis aboard accompanied by the various WY items implying the xenos were accidentally released while being transported to the colonyās research center. Though, depending on interpretation, either the shuttle crashed and then the lab was overrun by xenos as a result or the lab got overrun and the shuttle tried to escape the colony only to crash back down. The presence of USCM weapons in the corporate vault along with the nuclear authentication disk does raise some interesting implications.
Shivas, itās seemingly implied the xenos were in ice and defrosted? Thereās not a lot in the way of implied events. Canāt even really be certain the xenos attacked the shuttles here as the damage sustained could have pre-dated the outbreak. Though, again, conspicuous USCM weapons and tech located primarily where the xenos were seemingly being studied.
Solaris is comparatively clear. The xenos were being studied in the labs and escaped, likely due to either researcher negligence (as is the norm) or some kind of sabotage by what appears to be either a cult or the CLF based on the decrepit mining area in the south-west loaded up with guns, bombs, cash and revolutionary/cultist symbols.
Fiorina, again, the result of scientists studying frozen xenos. Could note the shuttle in the west armed with turrets but free of any corpses or the Souto promotional event that seemed to have had significant turnout and also been a significant holdout against the xenos. Though hard to notice in gameplay, the map does show the station having sustained structural damage, possibly from explosions caused by the xenos or survivors. Also looks to have been a cult here in the chapel that could have been involved.
Trijentā¦interrupt me if youāve heard this one before, but scientists researching xenos. I canāt really think of a possible cause here either, the research area looks mostly intact. Presumably they tunneled out and fled to the other spawn points. Thereās really nothing definitive about what happened out here.
Soro, we know the UPP put up a good fight by the number of xeno gibs you can find near the xeno start points. Evidently they became aware of the threat and their troops fought the xenos directly rather than hiding. We also can see they had time to pile up their bodies and bag them up, implying the fighting lasted for some time. As for how they got thereā¦I dunno. Though the north-east structure with the shuttle is described as a āclassified research stationā, it completely lacks any scientific equipment or anything distinguishing it as a potential point of origin. It looks more like an army base than anything.
Chanceās Claim, besides the whole FORECON element, does not offer much explanation either. FORECON obviously got called in, had their dropships crash and got seriously messed up despite having HEAP and an APC (mad L). There is evidence of a cult within the room in reactors with the nice armor, suggesting a human element to the xeno outbreak.
New Varadero, itās not too hard to guess an origin. The big crashed Pred ship is likely the cause, as it was seemingly carrying xenos for hunting. The Preds either bailed out of there or died in the crash (another L) but I suppose it would be interesting if it was established that any Preds on NV were specifically survivors from that crash. Of course, the ship has been there for a while for a dig site to be set up, but the xenos may simply have been dormant until provoked (and likewise, any Preds may have been in hiding waiting to recover from their damages and for the colonists to not have a 24/7 guard schedule on the artifacts recovered).
Little too sleepy to do any other maps, but you kinda already know with Antre and Hybrisa. Besides, itās a discussion thread, other people can contribute themselves, I donāt have to give a perfect comprehensive answer. These are my notes at least.
also I wrote way too much why did I do this to myself