Wow. This is great. I really enjoyed it, even thought I should've been in bed a long time ago. Bio is gonna be mean when I get to class in a few hours!
I don't like the floating boiler. I'd like it to be automatic. I don't want to waste my time waiting for it to get into their assigned places, and "damage" should be the default, not alphabetic.
This is... yeah. Too long. I play a few levels, then take a break by doing homework or watching tv, then come back, repeat. It's not fun enough to do it in one sitting, although it could've been.
Include personal best scores, so we can try and beat it. That would make training a bit less boring. Maybe some achievements to get (Get this high, you get an extra level up!). Just little things like that would make the game more fun.
Quit complaining about the prices. Just play the game. It's the developer's choice. There are those people who will pay, and the developers will make up from them what they don't get from you.
 "Defender's Quest (lengthy!) Demo")
 "Edmus")
 "Super Stacker")
 "Clockwords: Prelude")
 "Bubble Tanks Arenas")
 "SeppuKuties"){kind=icon}
 "DuckLife 4")
 "Zilch")
 "Kill the Heroes")
 "Factory Balls, the Christmas edition")
 "Arkandian Revenant")
 "Zombie Misfits")
 "Topsy Turvy")
 "Sushi Cat 2"){kind=icon}
 "Tactical Assassin 2")
 "Burrito Bison Revenge")
 "William and Sly 2")
 "Liquid Measure 2 Dark Fluid Level Pack"){kind=icon}