It's alright, but it seems too lively to be Zone's tileset. I think it'd be better with more monochrome metallic colours like silver and lead, rather than a copperish-briwn. Still, looks pretty nice to me.
A majority of tiles look 2d and are badly gradient shaded. The only thing I really like is the windows to be honest (reminds me of Assassination Classroom)
I don't think the shading looks bad. The thing about it for me is that I think it's to small. The doors for example. I haven't actually tested this updated version yet but I can already see issues with making the door larger. I will test it out and post an example later.
A majority of tiles look 2d and are badly gradient shaded. The only thing I really like is the windows to be honest (reminds me of Assassination Classroom)
I agree with SF. A lot of it is gradient shaded (which looks bad), and then there are other parts that aren't gradient shaded that are pixel art. Either all of it needs to be NPA, or none of it. I'd recommend none of it because judging on the parts that are pixel art-- whoever was doing it isn't very good at it.