I got to the final door and it won't open until I have a key. I've beaten every single room but there have been no keys in the entire level.

I don't know if this was by design or not, but there were several rooms that said "Ambush!" in that same level, but no enemy robots appeared.

I had the same problem, but most (all?) of the rooms which said "Ambush" ended up having robots when you entered from one of the other doors - just like the earlier levels. I did find a few places where you got $$ if you walked over a distinctive floor covering -- perhaps the key is hidden as well -- but got frustrated last night and gave up.

Aha. Replayed the level just now and found the key - it was not there last time I played it. The key is located on the left side of the screen, in the second vertical column of rooms, at the lower end of a pair of rooms hanging off of a loop -- lower left quadrant, towards the top of that section.

Annoying, but probably an honest uninitialized variable somewhere :-)

Off to L12

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