Guh, who decided ctrl, a key with so many other uses is the best key to jump in a browser game.
On a mac, ctrl + a direction switches to the widget panel, or if you're using wasd, ctrl + w closes the window. It makes the game unplayable.
Really $5 isn't that much for a game of this size. I get more play time out of this than almost any $60 xbox game and it's not like you had the buy the game first and buy the premium content after. You can play the entire game without the extra stuff so I don't believe this situation is as unreasonable as many people make it out to be.
 "Escape From ASCII Castle"){kind=icon}
 "GemCraft Labyrinth"){kind=icon}
 "Whiteboard Tower Defense"){kind=icon}