The Protector’s theme is… maze-like patterns!
His walking animation is also programmed kind of cool. The animation’s speed depends on how fast he’s moving, and can even be reversed.

Also, HFX posted a preview of the first boss theme: http://www.newgrounds.com/audio/listen/586743

This boss has been pretty fun to work on.
The satellites make it really easy to come up with interesting patterns.

He’s also quite interesting to fight, because how you take out the satellites is up to you.
You get points for time, so concentrating on attacking the body will usually get you the most points, but will also be the hardest approach.

The turtle’s theme is bullets that spawn on or bounce off the edges of the screen. So most of the patterns don’t look particularly impressive, but they’re still challenging.

For each boss’s last pattern I’m sticking in a super-dense graze-fest. Bigger bullets are worth more points!

Btw, all of my screenshots are on Heavenly difficulty.
Casual difficulty is about 25% density, Hard is 50%, and Heavenly is 100%.

Here’s a little preview of the Ice Golem boss.
Each boss will have 12 patterns in total: 9 normal ones and 3 optional super hard ones.
I even managed to blow myself away with some of these.

That’s 9 bosses so far. I’ll leave the last one for later.
Next up: Programming them! I think I’ll start with the ice golem.