I have made two more small changes: I corrected one broken shadow near Mario, and also removed the yellow color from the palette; at the last moment I noticed that the picture actually had 15 colors while the challenge limit is 14, luckily I still had time to change that. :)

cool bro

@eggy

Thanks for the critique. :)

Yes, there were many problems in the first version, I just decided to make a quick piece for the weekly challenge, and didn't polish it enough. :)

But I have now uploaded a better version, in which I have tried to correct those problematic places...I made some of those background objects bigger and added some clouds to the horizon to give a better impression of depth, and moved Mario a little bit downwards.

And also I polished the characters, now Kirby doesn't look so strange anymore (the first version indeed looked scary lol)...and Peach and Mario too are now a little bit better, although not perfect or 100% accurate, but good enough for this picture...may the fans of Nintendo be my judges lol. And Yes, it's a Finger. :D

The scenery appears smaller than it actually is compared to the characters, the clouds look flat, and all 3 characters look odd; Mario's body looks like it was mirrored, Peach's face and body anatomy look weird, and Kirby's face kinda creeps me out. And... is Peach doing that finger gesture thing?

In overall, you could've done better. It's not very good compared to your other works (although I admit they need some work as well). But that's just my opinion so I can try to help you improve. 

Reference images can help you if you're doing something like existing characters or sceneries, or if you're doing something based on those.