At long last!
Wow I was away from Newgrounds for so long that I wasn't even aware the fourth installment of this was already available! First off, congrats on such a great series of sprite flash, you are an inspiration to sprite flash artists everywhere.
Now then, you have a pretty nice preloader. The sound-effects and music are as crisp and lush as they can get, I appreciate the audio quality. I'm glad to find a sprite flash that doesn't have music that sounds like it was recorded through a funnel. The soundtrack fits in perfectly with the scenes.
I see that you started off right away where 3 left off, you even had mario do a Samus-esque wall jump. I find it interesting how you can add emotion to your sprite flashes. On another note, The nintendo sense of humor cracks me up to no end. The way that you render the backgrounds is second to none, I can tell you spend time and effort creating them. Hmm at first I thought the battle between Wart and Mario would be old school, but you mixed it up with some great creativity, humor and ingenious moves. Can't get enough of that retro stuff like when Mario visits the alternate world through the red door to get his feather, that rawks.
I'll pretend like I didn't see Wart's ass. As the series of MK has progressed, I've seen your flash skills become more and more superb, in this case the background zooming effects blew me away, you don't fail to disappoint. This is exactly why when I mention awesome flash artists, especially those that work with sprites, your name always comes up. My hat's off to you again Randy Solem.