I really appreciate that this artwork tells a story and has developed a fully realized character for Ariel that shows her journey to reach "lvl 99". While this piece is not as cleanly or expertly rendered as some of the other entries, I believe that you really put some though and effort into keeping the character interesting but also recognizable. The colors are really nice and Ariel stands out with her golden armor really well. I think to take this piece to the next level you could have done well with adding more effects to make it flashy or using some depth of field tricks to add to the depth of the piece.

This is very well rendered, but some of the shortcuts are a little too visible and there are some texture mishaps here and there.
This is very pretty, but in terms of the contest this was made for, I personally do not find this concept very imaginative nor creative. Let's be honest here, it's been done before by hundreds if not thousands of artists. Other than the horns on Mario's head, I don't see too much unique about this concept. It's nice that you sourced your reference, but there is such a thing as too heavily referencing another's artwork and style. It's fine to be inspired, but in the future, take the steps to make things your own. There are so many Yoshi tyrannosaurus rexes out there, but I like that the interpretation depicted here is a lot less skeletal (much less Jurassic Park) than some others.