Yeah, is shame.
Emmet seems to over-ride some fundamental inbuilt keys like soft undo, and scroll lines. The bindings are even configured to trigger in python strings which is quite annoying.
I stuck it in ignored_packages pretty quickly myself. But it's the future I guess.
You don't need a backup to access ZenCoding code if you really want it, just basic git skills to wind back a commit or two.
It's a pity neither Zen or Emmet don't have better multiple selection support. In both, It's kind of
bolted on hackily.