So I had my first terror mission on Classic Ironman that was nothing but chrysalids. It was the second terror mission. This is still EU, so zombies still chestburst into more chrysalids who can breed more zombies to make more chrysalids and you get the idea.
It was pretty intense. Killed 20 aliens in all, all of whom were zombies or chrysalids. Saved 9 civilians. Only reason I saved 9 and not 3 was because I apparently managed to kill all the chrysalids before they consumed everyone.
I had a pretty similar experience on one of my I/I games in EU, I wanna say my fourth one. My first terror site in that game wasn't entirely chrysalids, they also had a few squads of floaters. It was on that one cafe map, and during the start of the mission my squad got bogged down by the floaters, who took the high ground. The floaters killed a few people but we managed to take em out, but all the chrysalids had been doing during this was killing civilians. I was too scared to enter the cafe because I figured the chrysalids and zombies would just eat all mah brains in the close quarters, so we waited it out by the truck at the entrance. Musta killed about 3 chrysalid sqauds, and about 10 or so zombies and a few extra chrysalids. Only one civilian survived.
Waaaay later into that game one I had another terror site on the same map, nothing but sectopods. Was something like 7 sectopods, and I managed to set every single one off at spawn.
It was a bad day.
Managed to pull through, since I had almost max tech and quite a few of the sectopods just ran away after activating (though hunting them down was a pain, the whole "sectopods can shoot at people they don't see" really ruined my day.) Lost a few of my relatively unimportant people, but my col. sniper suffered a critical wound when they comboed a rocket barrage and car explosion to one shot him from full.