Here is how to get statge 40. Fire a shot in a random direction. If you don't win, move your mouse one pixel, hit R, and fire again. Repeat for all mouse locations on your screen. See also Ben "Yahtzee" Croshaw on Peggle here (http://www.youtube.com/watch?v=sKOp4vcb6RA) specifically starting at 1:30.
I'm not sure why this game is about a zombie killing humans. You aren't doing so in a way so as to make more zombies; you are using guns. It seems like the premise for this game would work better if you were a zombie hunting human. I just don't think the reversal adds anything.
Messing around on level 1 just to see how much energy I can have collected I learned something. No matter your maximum energy or collection rate, you can only be spending 32 energy at a time. So I was in this awkward situation where my energy was 1700/1700 and collection was 120 but I still had a huge deficit going. Moral of the story is any energy collection above 32 is more than you can spend.
The only weakness this game has is that it's not very hard. But given the core mechanic, making harder puzzles may be just more frustrating. So this game does well for itself but leaves more 'hardcore' puzzle fans wanting more. If there would be a sequel the thing I would say you would want to add is a variety of enemies (some you may have to throw your head at to stun or kill, maybe headless scarecrows who will attack your body but pick up a detached head and wear it, I'm not quite sure) or make a completely unrelated puzzle mechanic and focus on the interaction between that mechanic and the head-throwing to make a more difficult game that is as much fun as the original. Cross this game's mecahnics with something akin to Company of Myself's middle chapter or One and One Story and you'd have something quite possibly amazing.
The only thing I needed a walkthrough for was that I didn't realize when the world goes blue you can walk around. I also spent a lot longer than I should have when doing laundry. When the hot water heater is full I would suggest that the message when you use bucket on heater reference the easily overlooked pipe right next to it. A text-based or text-and-picture walkthrough would have been a nice addition. But other than those nitpicks everything was solid. No true 'moon logic' puzzles where the only way to come up with the correct solution is to have made the game yourself of find the walkthrough. Those sort of irritating puzzles are pandemic for games in this genre and you found a good place in the spectrum that runs from oversimplified "You have 1 item in your inventory and there is 1 interactable object. Use item on object, you win." and the other far end of "How was I supposed to guess that?!?"
I reached level 40, and have every upgrade. I purchased upgrades for a Tesla gun, that thing sounds like it'd be fun to use. The issue is, my 'primary weapon' is the Lazer gun, which is 3rd from the last. I get support drops for rocket launchers, 2nd from the last, but never Tesla guns. if Rocket Launcher were my primary my support drops would be Tesla guns, but I can't upgrade any further. The Tesla Gun seems to be inaccessable.
Followp to 9/18/13, if you build 1 collector and 1 turret, then as soon as both are charged build another turret, pause, send the charged turret to the furthest southest location it can fit on the top of the tallest cliff, the uncharged one exactly above it, and move odin city, that works. The one turret method I couldn't get working.
Still, this game gives no instruction on how to do this kind of mess. The random maps are just RNG without consideration for how difficult it is. Too much variation between highly casual and Dark Souls of flash RTS.
9/18/13 is rediculously unfair. I moved my base the ledge just south of the rightmost powerup, making an energy boost and a mortar. Barely had enough time to build mortar and not get destroyed, I spent the next hour inching foward, sure to build a drone hitting far off pools of high creeper. I eventually get a breakthrough, claim that peninsula and begin westward push. With the creeper on the largest mountain under control, "Survival Mode" kicked in and I lost in seconds. I've been a long time fan of this series and game but after today, I'm unfavoraiting this game and all of it's related games and changing all their ratings from 4 or 5 stars to 1.
Missed the leg in the wall panel in the first room on the left. Spent 10 minutes grinding every object against everything else. Once I found the leg, game beaten inside 60 seconds.
Try this one. Turn on engines, launch. (Do not have crew board, do not close the door) Drill Hole, Drop Bomb, Activate Bomb. The ending you deserve: See Earth from a distance. Visible explosion at N.A.S.A. headquarters. Brief pause. Asteroid destroys earth. Actual ending. "I Saved the World, but at what cost?" The cost was a rocket and a bomb. All the Astronauts were safely on Earth the whole time.
So, this is a game wherein the only way to solve the "puzzles" is to read the walkthrough. I say this because of stage 15, which admittedly becomes rather simple if you find out that you can use a sign to change gravity. If for some reason you just started playing this after having walked away from it for a considerable amount of time, you might try pushing furniture around to get the boy with the key up to the lock. This isn't a puzzle game, nor a physics game. It's garbage.
As someone who has been disappointed by the last dozen physics puzzle games this site has seen, I just wanted to say thank you for restoring some lost faith. You do quite a lot with very simple puzzle pieces, and in this genre level design is probably the most important thing. There's not a great deal of challenge for veteran players of a large catalog of physics games, but you really explored a lot of ground with only 3 kinds of ghosts, and it is clear to me that a sequel with only a few more kinds of ghosts or some other game play element could reach out to more hardcore puzzle fans. I'm glad you kept it quite simple; this kind of game doesn't need a wisecracking support character / inexplicable love interest who is psychic and uses dynamite to destroy special color coded bricks. Less is more.
The stage with the bunker is not friendly to solvent. I dissolved the bunker entirely, and it refused to acknowledge my victory. Then on a replay it wouldn't register me having destroyed the bunker when I used the bomb you're supposed to use. And at some point, the memory super-overloaded.
Loved the idea, control scheme ruins everything for me. When doing the velocity jumps, just give a "shoot straight up" or "shoot straight down" ability. Being third person perspective shooting is a lot harder than if you were actually playing Portal.
Interesting mechanics, level design is irritating. Death counter included only for the purpose of annoying players who get frustrated. There is a difference between challenge and nuisance and the many many deaths you will suffer here are the later more often than not. Like having four teleporter entrances corresponding to four exists, putting instant death spikes around 3 of them, and randomizing which entrance connects to what exit. What purpose does this room serve other than to pad out death count?
 "Jack the Zombie"){kind=icon}
 "Enough Plumbers 2"){kind=icon}
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 "Humanoid 47"){kind=icon}
 "A Second Chance"){kind=icon}
 "All That Matters"){kind=icon}
 "Rolling Ghosts"){kind=icon}
 "Mushroom Cloud"){kind=icon}
 "p.i.g"){kind=icon}
 "Antichromatic"){kind=icon}
Thank you Kenaron! Really useful feedback!