(First off - I’m not sure this is the right place; I was trying to find a bug tracker.)
I just started trying Atom, and first launched it via spotlight (cmd-space atom ); this seemed to work fine, and opened the welcome text. cmd-shift-P also worked.
However, many other chorded keybindings don’t work. eg: cmd-t does not respond, cmd-shift-t (the documentation shows a capital ‘T’, so I tried that… did re-open a closed tab, though). ctrl-0 also failed, so it was very difficult to actually open a file.
The buffer navigation keys /did/ work (ctrl-a, ctrl-e, ctrl-p, ctrl-n).
I’m running on Mavericks, generally using dvorak, but I tried with a standard US Qwerty layout as well (I was actually happy to see that the behavior was the same with both).