This demo is great fun! Some of your music choices and things like the searchlight intro definitely summon up the spirit of Conan / Lupin / Saint Tail / Cat's Eye &c. Having time to spend clicking around and working out a solution fits the premise very well. I think the only thing that threw me was something very minor: the pillar box outside Ramona's (postbox, mailbox) was surprisingly short; those things are normally shoulder-height. But that's hardly a problem, and actually I thought it was kind of cute.
Good luck working on the rest of the game! I'll keep an eye out for it coming out.