Wow, this is probably one of my favorite games that I've played so far, no exaggeration. Just getting my nitpick out of the way, I would've preferred the sprint/run button to be left Shift instead of D. But honestly, that's about it; I personally like platformers with interesting mechanics, and this was simple yet straightforward; crouch jumping felt really good to control.
I really liked that you had to go between houses to get the right keys that opened doors, it felt similar to a Metroidvania in that sense. The jumping felt good, the movement felt solid, and the houses weren't too big, so I wasn't getting bored moving from house to house. The boss fight at the end was the right level of challenge for me, and I thought the little text pop-ups at the end were interesting, kind of like you were implying some story behind the player character.
All in all, this is a fantastic entry! Gameplay felt really good, the exploration theme was conveyed very well, and the presentation is quite solid. I could see you taking this concept and just adding more levels, or more houses with keys/locks to build a larger game. Excellent work!