Merry Christmas/Happy Holidays all!  Enjoy Demo 2!
  --FirePhoenix

Demo officially ends after getting Varia Suit, however there's lots more bonus stuff to search for.  Varia is just the beginning. ;)

Please note that after Varia, no major upgrades except for one of them are in their true locations.

Item Totals:
58 Missiles
11 Supers
9 Power Bombs
Morph Ball
Bombs
Ice
Varia
Speed Booster
Grapple
Spazer
Boost Ball
Power Bombs
High Jump
Charge Beam

Known issues:

Ice Beam's pickup palette has not been fixed yet so it looks a bit odd.  Requires hex fixing I haven't done yet.
Hopefully all areas that you shouldn't enter are blocked off.  Sorry if I missed a spot.
Always keep your Power Bombs close to full to avoid accidentally getting trapped in certain areas of Gaia Heights.

Small hint:

There is a point to entering the elevator room in Therma. ;)