Technically, this starts to look very fine.

I have two major problems with the layout of your landmasses though.

First one: you fell into the "fill the space" trap - resulting in the basically straight northern and eastern coasts. Second, your coast is too consistently chaotic. The resulting continents appear to be frayed, which is very recognisable in the thumbnail and the scaled-to-screen size.

I think you got various very interesting shapes which might be fantastically suited for regional maps, but for a world map I don't think this will work out.