Excellent Quest began as a small, self-development project to help the author become more familiarized with coding in VBA. As he began to realize the full potential of what he was building however, it was decided this should be a fully functional software title made available to everyone.
In its infancy, XQ had a simple '[X]' displayed as the character location on the screen, and the user needed to click the 'North', 'South', 'East', 'West' control buttons in order to move this character. As the project evolved, insertion of graphics for the character position and movement via reseting the functional keys on the keyboard (arrow keys), enhanced the user experience immensely. Additionally, it was later found that a double-click to equip or cast for inventory items and spells respectively, allowed for a much more intuitive user interface with the game.
Originally, constraints were enforced by simply moving the character back off of a barrier if they moved onto it (which resulted in a "screen bounce" effect if you continually tried to cross a barrier). A new constraint system was then developed which caused barriers to act just as that, and the character is halted as soon as it reaches one from any direction.
The last major development to be made is the copy protection which was added to the software, preventing users from simply copying and pasting their validated full versions to their friends, and making each copy of the software specific to the machine which it is located on.