I must admit, this is an awesome looking game. I'm assuming you made these graphics yourself, correct?
I only have one problem with some of them... The wall tile there where you exit comes to a sudden and abrupt end; any way to make them appear like their curving around the corner instead?
Also, with the next image over, where you have pillars int he water? The pillars look really odd - as if their sitting on top of the water instead of in it. Maybe try to make the bottom portion either an event for water or maybe have the bottom portion of the pillar appear some-what transparent. Just a thought...