This is amazing. I like how they look like they've already been through a few fights and have those dents and scratches on them, yet they grin widely and with determination. I also love how you used the Mario & Luigi art style for Mario. I never knew it would fit very well with toon link. that. You portrayed it very well.
The one thing I can't get off my mind though... Toon link's feet... where are they? I don't remember them being that small to look like peg legs.