It's a nice start. But besides adding a little more detail to the map, try making that hallway a bit narrower too. How many people can usually walk down a hallway side-by-side? 4? 5? Try to think "small" when mapping interiors, as the results are often more pleasant the less empty space there is on the screen... Also, try to avoid using "pillow-shading" for your tiles, and if you're going to use a dark outline for your charas you should give everything else the same outline so it doesn't look like you're mixing styles.

Btw, I like the art a lot. It's a bit of a mix between comic and manga. It'd be interesting seeing the entire game following this direction.