I just wanna say a BIG thank you to everyone who has critiqued my entry for this Ludum Dare.
The comments have been very inspiring, and has motivated me to continue working on the mechanic.

Some points in response to some of the comments:

• Making use of the mouse is actually to keep the right hand occupied, because its really easy if both hands are available to press keys on the keyboard.
• Only 3 ports can be selected at once because that is the maximum keys on most keyboards that can be sensed.
• The representation of trading seems to be too confusing for many people, I’ll change that while keeping the core keyboard twister mechanic.
• And er… sorry about the lack of levels.  I just couldn’t keep my eyes open anymore at 6am.
• EDIT: Someone asked for the sourcecode of the game, here’s the .gmk file:
  http://xmashed.com/games/keytrader_source.rar

Thank you all for your suggestions and feedback.

With Gratitude,
XM