I really enjoyed this. First time I got caught trying to solve the puzzle of "how to crane" which is honestly a great puzzle. The whole game felt very satisfying. Every construction site needs pirate-style treasure chests filled with cash! The rush after the alarm was triggered, pushing my luck at the Louvre, frantically figuring out the crane again, etc. I actually beat it with 0 seconds remaining. It was a very tense moment, quality heist game stuff! So well done on the game.
On my second playthrough I couldn't get enough $$ to progress beyond the office. I kept going back and trying to find whatever I had left behind but to no avail. My first play through wasn't a problem, 1st play through I made it to the construction site. So I refreshed the browser and tried a third time and everything was fine. I'm not sure if I just missed something or not, I was $498 away from my $10k target. I also opened things through walls in the office.
I never considered the dragon heads and I don't know if I had anything activated at the end or not. I learned how the mechanic worked I just didn't bother with it. It seemed unnecessary.
Overall I think the polish, visuals, game feel, duration, and fun are just great.