They're all possible:
This first level is very interesting and quite possibly the MOST difficult of the 3. This level veers much closer to strategy than puzzle I think. The primary reason being that if you fuck up at any point then you're dead. It's seems initially fairly clear how to go about achieving the goal but in reality it can be rather more difficult. A fun, yet somewhat frustrating level. If you'd rather not, then skip it with 'P'.
You really have to understand how the game works in order to beat this level. The main reason I think this level is more difficult that level 3 is because I removed as many red herrings as possible.
Having designed these puzzles, it's very difficult for me to say whether one is objectively harder to solve. The reason I put this one 3rd is because I figured that anyone who got this far is probably willing to put in the time to solve it, whereas if I put it first I think people may be put off the bonus levels. There are a few crazy moves you have to pull off in order to beat this level but the main difficulty point I think is figuring out how to go about going about solving the puzzle; which characters you need where and when.
Super secret BONUS LEVEL. This level is a secret. The only way to get to it is with 'P'.
The reason I made this level so difficult to get to is because you actually have to exploit a glitch in order to beat it. I wasn't sure if this was fair or not so I panicked and got rid of the link. The level is still in the source code though and you can still get to it in game.
I may actually like these level more than the actual levels. I might consider making this way of designing levels for this game into it's own game.
I'd also like to create a top down version of this game.
And I'd also like to make an instrument.
Nevertheless, time is precious at university so I'll probably be spending a lot less time making games from now on (even though I'm taking a course in 'making games').