Success! It's not laid out as your snapshot indicates but I found the Activate command. Played for an hour and a half, and posted my first bug report, all inside Steam. I'm very proud of myself.
Game play very much as I remember it, but I have to bind those keys!! Body memory is making fingers twitch to unassigned keys.
X for Exploration mode, for example.
Pretty darn nice, Mark! Take the rest of the year off, why don't you?