it is FINISHED and presented to the boy. it's knit with stockinette, and the characters are stitched on using duplicate stitch. the black yarn is malabrigo, and the other colours are various superwashes. before going on to the pics, i'd like to thank this community for being so helpful and friendly while answering my questions. you guys totally rock!
the giftee and the aforementioned scarf
closer inspection reveals that one side has normal super mario characters on it...
and the other has the smushed/dead versions of the same characters on it. the ghosties, fireguys and stone turtles are on both sides cuz they don't die.