Thread title made me click, haha.
Overworld
I know this is still a WIP overworld, but I already like the start you have there. Good land structure, and it has a new, fresh palette. My only complaint is that it's a little bland, but I'm sure you'll fix that up soon enough.
As for the Mario/Luigi special world palette thing: Awesome.
Level Design
Not really enough screenshots to get a good grasp, but it all looks pretty good.
Graphics/Palettes
I like your graphical choices. A lot of them are less-used than others, which is good to see, considering the amount of hacks that all use the same tilesets. I really like the background in the fourth screen (in the OP), though.
Misc
Really cool title screen. Fits the hack very well.
Errors
I see none.
Overall
Looks good so far from the little bit you've shown. Nice stuff.
IRC Quotes (
March 20th update!)
/MKICK 4: Flantastic Puns