Pretty amazing mission. A bit difficult though.
I found the (navigation) map a bit too vague and thus almost unusable. A lot of locations can only be accessed via other buildings, but this cannot be seen on the map (no clue). There's a long road that is completely not accessible, but because it looks on the map a regular street I put a lot of effort into trying to reach it somehow, although actually it's a fake road. Also no street names anywhere on buildings doesn't help.
I noticed that the mission outro can only be played once. If I try again, the animation halts. For it to be played successfully I have to restart tdm.
Also, during that scene with the player looking at the painting in a chair, you are physically still in the location next to the drain pipe lid. Because you can swing your blackjack and hit the lid and you hear the sound during playback.
I was wondering why during playback in the center you see a giant cursor:
Edit: I was looking at the original video file and it does not have the giant cursur in it. Maybe a gui or mtr related bug?
Btw. I noticed that some things, like the streets looked very similar to your newest mission that I betatested. Maybe it's supposed to be the same city?
Where can I find the ring that is lost in the museum?