1. Shading is very inconsistent or non-existent. Make sure the perspective is right and the shading goes behind the wall.

2. Wall height is inconsistent as well. This can make or break a level, so you should guarantee that the proportions are consistent.

3. Lots of overlap between trims, try to not clash two "outer" trims next to another, for sake of perspective this is confusing and creates a lot of visual noise.

4. This level feels very bare and open. Try to add more furniture, maybe glass tables? I'd suggest dividing the level into small rooms such as a kitchen, which could have stairs that lead down to a living room, etc.

5. Overall this level needs more NPCs. I know that not all players have access to a large variety of images, but spice it up with some lights, windows, paintings, couches, counters etc. This level feels like a template house.

To conclude, this level's "Skeleton" is functional, and with a few tweaks could make a great canvas for you to paint some NPCs on.
Make sure to rework the perspective when it comes to shading, make sure everything is proportional, and watch out for small tile errors (Especially on the floor on the right side, those 3-tile floors are tricky to work with.)

Best of luck reworking this and making it a complete final product!