I'd say that the angling of the tiles looks fine, I think the math mostly works. I would, however, suggest adding a bit of shading. Right now, it looks a bit flat, and somewhat strange because all the tiles look the same apart from their orientation.
I did a quick mock-up to show you what I mean:
I'm not entirely sure where your light-source is, so the shading is prolly incorrect in this example. It's mostly to show what I was talking about with differences in coloring though. I haven't added any new colors to the blue tiles, they all still use the same 5 colors as the original, but there's a bit more depth to them now, I believe.
Being from the third world, I reserve the right to speak in the third person.
Using Editor version wip 20170527 gfx_sdl+fb music_sdl