Yeah, it was good. I liked the level design (especially the 'reveal connections' blue key thing; the sense of revelation you get upon hitting those, or the white keys; I imagine the resulting modularisation of stages made things much easier to handle from a design-perspective as well).
Yeah, the white keys and blue directory nodes turned out to be an important part of the design. Every other component in the game is time-limited, so players have to be quick. Those two serve as a sort of checkpoint; once you get one, you can relax and recover before figuring out the next part of the stage. I think that's what you meant by modularization.
As a matter of interest, do you have any feelings about it yourself? Have many people made use of the level editor?
I'm really pleased at how it turned out. One thing that was awesome was the music; I had the game basically finished when the composer approached me, and he did an amazing job capturing just how I wanted the game to sound. He's working with me on another title, where he's done the same sort of magic.
The game's gotten over 75,000 plays in two days, which is awesome. And yeah, there's been a lot of folks posting levels in the comments. Some of the levels are very good, some are uninspired, and some are dumb. One thing people really like to do is fill a level with the purple divider blocks and just let the packets multiply. Luckily, I anticipated that and put a cap on the number of packets that could exist at once, but it can still slow the framerate down when there are 100 shots on screen.