i played a few sessions of Trespasser and had a great time! i really like the abstracted action system for the different timescales- it saves a lot of table time.
our characters got eaten by bugs trying to retreat from a freak random encounter. we failed the group initiative check three rounds in a row. we felt very powerless against the dice- there aren't any combat actions which make retreat more likely to succeed, so all the trespassers could do was keep fighting a losing battle.
retreat should definitely be costly, but we do think there should be tactical decisions which support a need to retreat. for our own game we've cooked up the "Retreat Round", where the trespassers declare they want to retreat and then the enemy gets a full ambush round against them, after which any survivors automatically spend endurance to escape. we think this will keep retreat feeling risky while engaging better with the other mechanics of the game.