Yeah, I think the main problem is that the style is not uniform, which wouldn't be that big of a problem, but, as Calin said, the different resolution really make it look weird. Plus the characters sprites look a bit cartoony compared to items in the background, and as I can figure, this is supposed to be a serious game (though on second thought that might not be the case).
Design wise, backgrounds don't have focus, or to be more precise they're not really optimized and adapted to gameplay
- 1st background, while showing the building, the part where things are happening is just a small part of the screen and thus as whole the background feels a bit unused
- 2nd background you should turn that table into a corner shelves and counter thing, maybe even a table in the middle of the room and place the devices and other hotspots. Not only is this setup unreal and boring, but when you play the game, the character sprite will probably block one or more other hotspots. Would a room really be setup like that - everything empty but 1 desk on one wall
Hope that gets you started on the right tracks.