Possibly. I've experienced several emotions during enemy turns, but boredom isn't one of them.
No, I mean the time it takes to go through the alien turns. There's lots of waiting in between their actions. I don't know if that's a setting or something. It's like:
Alien 1 moves
Pause
Alien 1 fires
Pause
Pause
Alien 2 moves
Pause
Alien 2 fires
Pause
Takes ages. Maybe it's my computer?