To try to use a game that is as polished and unique as Garden Defense as a model for yourself to work off of...when the results are so slow and beneath the original...probably not a good idea. Perhapse try improving upon the gameplay...perhapse try making your game unique. Take cloud's advice and check out towerdefence.net....take a month and finish all games there ... then you will have a good grasp of what a good TD consists of and what makes a TD bad or boring.
well I made one..lotsa fun...I must say though that the restrictions really put a cork in my creative juices...inputting an amount or number only to see it changed for a cap..mmm..talk about anticlimactic.
That's my only complaint...although I found I ran into LOTS of limits that I could not understand why they existed...I'm not a game programmer..I just didn't think it made sense to cap the stuff.
 "Straw Hat Samurai"){kind=icon}
 "Bloons Tower Defense 3"){kind=icon}
 "create your own tower defense"){kind=icon}
 "Whiteboard Tower Defense"){kind=icon}
 "Shark Ups"){kind=icon}
 "Little Fish in a Big Sea"){kind=icon}
 "Kaleidoscope Reef"){kind=icon}
 "Atomik Kaos"){kind=icon}
 "Garden Inventor"){kind=icon}
 "Banish Land"){kind=icon}
 "Tactics 100"){kind=icon}
 "The Necronomicon"){kind=icon}
 "Murder In Rayville"){kind=icon}
 "the i am bored so i chat game"){kind=icon}
 "Alio's Army 2- Infantry Under Fire"){kind=icon}