fleet depot
The first thing I notice is that the level is almost completely grayscaled (so far). I think it works fine in the beginning, but if it continues after the first ship part the level might become too boring to play from the start if the monochromatic part drags on for too long. This could be easily "fixed" by subtly implementing a few colors in the first cube part to make the decoration more interesting, e- g- in the pulsating squares inside the structures.
Another issue I see, or at least something that could have been made better, is that the theming is not very strong. It could easily get mistaken for a normal generic looking level, especially when it's monochromatic. This can be fixed by including more elements that are clearly city-themed, such as tall buildings with windows, or a city-looking background. Using colors can help accentuate this a lot too, which can also solve the first issue.
arctic lotus
woeful kite