With good Pep pieces as a starting point like this, you're sure to have a great ODST suit in the end. Well done!
Regarding the SMG, it looks like you're making it out of corrugated cardboard? Have you considered using foamboard? You can get large sheets for $1 from the Dollar Tree, and I find it makes a great weapon-building materiel considering it doesn't have all the empty space inside, and you can carve and sand it to shape.
Keep up the great work!