Choosing an upgrade is like playing the lottery. Sometimes it actually gives you the upgrade and sometimes you find the exact opposite of what you picked in the store.
Unbelievably intense game. As for the idea of the story and the execution I must say, it is one of the best flash games I have ever played. Story wise it is the best flash game of all the ones I played. SDGS has a soul ;)
here some hints for you lost souls:
-water the desert
-use the tree the fat bird sits as catapult to get rid of it
-change angle of the ramp
you've got to figure out the rest yourself
 "Wild Wasteland"){kind=icon}
 "Galaxy Siege 3"){kind=icon}
 "The Infinite Ocean"){kind=icon}
 "The Visitor Returns"){kind=icon}
 "BOWJA THE NINJA (on factory island)"){kind=icon}
 "Typing Ninja Hunter"){kind=icon}
 "Path of Honor: Chapter 1"){kind=icon}
 "Super Energy Apocalypse : RECYCLED!"){kind=icon}
 "Boob The Happy Triangle"){kind=icon}
 "Escape from Palmisland"){kind=icon}
 "Mission IIM"){kind=icon}
 "Line Of Control"){kind=icon}
 "Robotics"){kind=icon}
 "DayMare Town 2"){kind=icon}
 "Submachine4: the Lab"){kind=icon}
 "Anaksha: Female Assassin"){kind=icon}
 "P.O.D."){kind=icon}
 "Foreign Creature: The Unforgotten Mistake"){kind=icon}
 "Sprout"){kind=icon}
 "Easter Piece by Piece"){kind=icon}