Not only one Thief, however, but many! Being careless and getting the attention of more than one at the same time would be a disaster. The rest of the level has areaz similar to the original but the layout is a little different, especially in the south (starting) area.
After almost three months i got back to playing these levels.
This one had great improvements and still was able to keep the original level's atmosphere in my opinion. I didn't think it was possible to kill those two gauntlet gruntz but apparently so i skipped them at first, after making progress i realized it's possible, because i had to. The part with five thief gruntz seemed too much but i guess it was for the "thief" part of the level.