this packages disables your arrow keys in the editor. it's to encourage use of the emacs inspired osx shortcuts to move the cursor, and generally be rad at moving text around.
atom's list of keyboard shortcuts in the keybinding section of the settings screen is a very helpful complement to this package.
apple's comprehensive list of shortcuts is here: http://support.apple.com/kb/ht1343
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.