The smoke ring mechanic is pretty bad to pull off, makes it somewhat unplayable when you have to do a few in succession. 0.1 second off and "oops". Otherwise like the game.
shields at 20, guns at 19, get 2 guns, first deals 19 to the shield, the second only deals 1. This game has a lot of flaws and problems. Sometimes you can't select a target, and the list likely goes on.
I sorta wish there was a control setup for the mouse, would be much easier to dodge bullets... then again, this is a slightly more creative way to pull off a game like this, so I'm not complaining much.
Erm.. to follow up on my previous comment, this is the first level where speed shouldn't be as much of an issue. Likewise, this issue becomes more apparent the faster the speed is set.
Hmm... This game has 1 problem that I seem to see recur, the swordsmen units aren't engaging quite fast enough. They'll be in front of said enemy in line, however will not engage until enemy unit has passed, whereupon they chase it until it's out of range, and then simply don't engage it.
If the names of the levels were included, some things would be really obvious. O.o "That looks like a cloud... nope whirlwind... oh, okay, just change that square there..." Which is very similar to pixel art.
There begins to be a point where coins get to be rather pointless... maybe add some 'outfit' pieces that cost coins. The multi-color skins would be a good one to put under a coin tag.