Well, lets start off with the more obvious ones that demand attention.
Update Mark V to release (add and fix things.)
Remake the old Mark 1 and 2 suits (make them vanilla as well.)

MISCELLANEOUS:
Make Physics gun (Gmod styled.)
Make Super Gravity Gun (just color it blue and make stronger with one extra feature.)
Make HEV Suit (Mark 4 HEV with permanently detachable helmet as decoupler can't recouple.)
Make the Strider's warp cannon.
Make The Aperture Science Handheld Portal Device. (Will include at minimum of one mod - Simple Portals.)
This is just a little teaser. Also, don't ask me about anything related with the whip.