It's not bad, it just sort of defeats the purpose of the activity! I mean you're welcome to do them, and I will happily collect them for the first-post collection at the end of the activity. But the fun part of the activity is not adapting 2d, tile-based platformers to a 2d, tile-based platformer (e.g. Another World & Prince of Persia). The fun part (I thought anyways) is to take some really "advanced," next-gen, 3D affair and turn it into an engaging super-low-tech 2D game. Like, for example, it says in the activity instructions, and is featured in the banner and the first 10 or so submissions!
So again, make all the mockups you want, I mean at its heart that is what these activities are for. However, you should not express too much surprise that some people are confused about your choice in games!
Also, the margins between your blocks are too thick, your diagonal tiles have sharper corners than your straight-on tiles, too many brick outlines in the background (they get repetitive), a running pose will look more identifiable for the prince, the pillars appear fragile and overly thin, and the prince is far too tall!
OH, and I almost forgot, how come you started a whole new mockup when your old one had received critique and was not nearly finished?
