From paper to living enemy

I am not a very good artist. My line control is unstable. My circles are rarely round. And while I can use graph paper to make geometric shapes that are based on moving from square to square, I have difficulty making free-form drawings that are in any way symmetrical.

So, I fudge it. For something like the spider queen, I drew one half of the queen until I was happy with it, and mirrored it.

First I drew her on lined paper, then scanned it in.
Next step is to use paint.net to turn her into a monster.
The four images above are:

• The original scan
• the original scan minus the paper lines
• Then I mirrored the original image 
• Then I colored it

Then I "animated" the "test", by making a bunch of frames where they were in different positions, and the result is thus:

  

For the "Polygon of Horror", the boss is protected by shield generators that look like this:

 

They spin. And you might notice that it's more or less perfectly symmetrical. 

• Drew just the one arm as two separate pieces
• Scanned it in
• pulled the paper lines and artifacts out of the image
• Then I assembled the two pieces as separate layers
• Then copy/pasted the arm 3 times adding 90-degree rotation each time (for a total of 8 layers)
• Then I started coloring it in.
• The smaller center piece is just a scaled down copy of the the outer piece
• The center circles are little bit of cheating,
• I didn't actually draw those by hand, but rather decided once it was in the game that it needed a little "ejector" from which nastiness (for the player) will spawn.