Fantastic feedback, best we have had yet :)
Sounds like you had to pull out all the stops to accomplish the mission. There was a bit of worry that it may be a tad to hard for the player. But seems like you enjoyed the challenge.
Take your point re the outro.
As for the "veritable slide show" Yup, as you pointed out the UPS does a lot of the damage (actually there are only 4 groups and a handful of units using UPS in the City itself, most other non-city groups are deleted when you reach the city) but the city textures sure don't help. I'm not sure re the barbed wire and objects as these are fixed objects so once they are in place they should not take much proccessing power. I guess its a case of getting the balance right between trying to create a "City alive with movement" and it still being playable. Your sys looks reasonable, have you tried overclocking?
There will be V1.2 available next week so I'll try to tweak the city stuff. Yes, it could be worth another go as there is quite alot of different stuff to experience depending on your choices and the final act can be done in many ways. If you give it a go let us know how you get on.