Sketch 3 has a name which for me means that it has started to evolve within itself as a star alone piece. It has a post-industrial ambient vibe and is probably played at too fast a tempo here . Could slow down 10-20 bpm.
It is based around a progression in Ab with a bridge in the key of G. It works with b5 changes as it progresses through a series of key changes. I think that the textures could be built up along with some synth overlays and some electric guitar pieces as well as appropriate percussion.