After reading some more comments on other maps, I got convinced that a small part of the map is to slow. So I'm going to fix that.

think it's fast enough now

Made a series of changes, mainly cosmetic.

I don't like this abrupt change from grey rock to red bricks. See screenshot, or look at bottom-left of screenshot submitted to this site.

In addition, there are some strange textures at some places on map, but this could be my own taste.

In that "center" place with two bullets and two rockets (and some health), maybe you want to break that 8x8 K-orner into 4x4 or less. Why? Because cube still treat that as a 8x8 "normal" block, instead of an angled block. You may change, if you feel you want that. Or you may change that "circle-shaped" thing in one "square-shaped" or "square-shaped-with-small-korners".

One more suggestion: make the "handrails" one cube lower than they are now. It is the first time I see handrails in a cube map, I think they are a nice addition, but I feel they are a bit too high.

Ah, nice map. :) Parts of it remembers your map "003". That's a good map too (although very slow). You should submit it too.