I remember there was a protein icon that was fixed to not look like a shoe. I too like the blue theme more. We definitely did not decide to use ATP as a health measure. Health shows how well all of your organelles are working and how damaged you are in general, and works in conjunction with ATP. Check out the bottom half of this post.
I also really like the suggestion of using a hotkey for suicide and having suicide pop out only if you have a small amount of compounds.
Anyway, I think what you did looks great and very professional. Nice job.