Gravity Hook is a flash game created by Adam Atomic and Danny Baranowsky way back in August 2008, and marks their first collaboration. It was based on a typing-tutor prototype game called Gravity Key, created by Arne Niklas Jansson. Arne gave his permission for Adam to develop a mouse-based version that scrolled onward and upward forever. The original Gravity Hook was created in 5 days on a very early version of what is now the flixel framework. Gravity Hook received a lot of praise but also a lot of well-deserved complaints about the difficulty of play. Gravity Hook HD is a chance for Adam and Danny to revisit their first project with an extra year of experience and see if they have anything worthwhile to add. New graphics, new sound, new controls, and new gameplay make HD an entirely new game. For those hardcore fans of the old version, we've also included a special treat! But you'll need to climb at least 500m to find it... Source: The Game Website.