I'm on my first XCOM: Enemy Unknown playthrough on Normal and am just about to enter the end game. I've finished the Gollop Chamber and got one of my soldiers ready to use it.

However... I'm kind of an achievement wh*re, as such I'd like to complete as much achievements as possible on this easier run. I'm planning to start a Classic Iron Man after I've finished my current one.

I haven't captured all possible aliens yet (like Sectoid Commander & the Outsider) but as I'm currently in the end phase, I'm not encountering them (although I seem to run in a lot of thin men).

Does anybody know whether it's still possible to get my hands on those types of aliens this late in the game? Thanks!