This is a good start. I think the biggest things that need work are materials and lighting. Why are the walls so shiny in the first piece? Gather photo references of real world walls, and examine closely what their materials look like. Then replicate those materials. Secondly, the lighting needs finesse. Again, examine…
Definitely watch this talk, it's inspired how most anime and cell shading art styles in games are done today. https://www.youtube.com/watch?v=yhGjCzxJV3E