It took me several playthroughs over three days but I finally found all three diamonds and escaped The Spooky House!
There is no Android download but the web version works perfectly on Firefox for Android, with a nice on-screen D-pad and buttons that adapt well to both portrait and landscape mode. I also played through the Linux version, so convinced was I that my failure to progress was a bug. But it was not!
I did not expect so much gameplay in so few bits. The puzzles are devious because the simple graphics misled me into believing that the gameplay was likewise simple, but this is no fetch-and-carry game. The hints were obvious in retrospect, but this game was much more of a challenge than I expected. It made me observe and think. I was ready to call your game hint hotline (is 0900 SPOOKYSOFT a thing?).
This game is also memorable for its loving attention to detail, from the cat animations, to every single painting having its own evocative description. A fine achievement. Thank you.