Alrighty, heres my review.
Snowman
Not bad in terms of accuracy, some your notes a incorrect. Mostly in the runs that you have. Overall, pretty good arrangemet.
Ridley's Hideout
Not a bad arrangement, you need the second layer of notes in the 16th note runs. Overall, Not a bad arrangment.
Ending Theme, Super Metroid
The arrangment can use plenty of work. The bass line in most of the song is redundant. Not all of it is the same note thoughout. There are little mistakes here and there.
Good Friends, Bad Friends.
Needs chords in various places, including the intro. Chords set the mood and feel, these are very important to the song. Overall, not a bad arrangment.
Mother 3, Love Theme
Pretty good arrangment, feels incomplete in some places. Only because there is not chords backing up those notes.
Unfounded Revenge
Not bad, but phrasing and style is an issue here. The original has a latin feel to it, therefor you need to give it that latin feel. Note accuaracy is ok, but the arrangement itself could be much, much more intense.
Thats pretty much my review, hopefully it will help you in accomplishing what you want. Happy arranging.