I removed the C-Ships (purple spinning enemies) to unclutter the level and make both the D-Bomb Ships and C-Ships feel more exclusive to their levels.
I think I am happy enough with the second level now to move on to focusing on Level 3. My main goal is to find ways to encourage using the 2x1 and 3x1 blocks. Up until now, those blocks are not always as advantageous as the 1x1 (though new players do not realize this at first). Perhaps the E-Ships will touch upon this, but the new boss will certainly incorporate some sort of advantage to using larger blocks.