played this in a pug yesterday, I was surprised becuase it was fun as hell to me.
just a few thoughts:
mid is very cool, you might want to consider downscaling it just a bit.
second has some crazy sight lines but other than that is cool
last is actually really cool. you may want to find a way to make secret a little bit more visible to the team holding, it seems like teams can push thru there right into the point, and makes backcapping pretty damn easy.
but either way for an alpha this map is impressive as fuck, I can see a lot of thought went into it and you made a really unique, cool looking map. very few complaints from me, keep up the good work and keep working on this map, it has huge potential.