I have no clue how to get the specials. Even if I connect them like in the example pic, no special is listed in the properties (and I don't see anything special happening). Do they have to be upgraded beyong level 1 to work? (A save function and keyboard shortcuts to sell/upgrade would be nice btw). fun little game for the rest, but frustrating as you have no clue of the exact mechanics.
 "Pixel Defender"){kind=icon}
As it mentions in the game, all towers must be fully upgraded to link together. I'll add hotkeys for upgrading and selling soon. Thanks.