I recommend that you start as a necromancer, he has a rapid fire attack, can heal him self (i suggest doing this while there are no enemy's around) Plus he can summon creatures! These can be useful when jumping a gap and pressing the button right when your over the enemy!
This is a great td game for your first try, but it really needs a speed up button. Also i love see td games that give you options for the upgrades. Lastly i think you should add a poison tower that spreads through out the enemy's!
this is an awesome game! but i think that they need to,
-add different zombies with different ability's like fast zombies, zombies that clone themselves, ect
-a few more upgrades such as fly, invisible, ect.
-more citys to fight in
a "mass attack mode" where one level has 100 zombies at one time and you must stay alive!
- and maybe a few more weapons! :)
well this is a fun little game, i would suggest you make a sequel! but with the sequel i would like to see an undo button! i cant tell you how many times i accidentally pressed the wrong button and had to start all over! if this could be added i would be very happy :D
even though its a copy its still really fun!!! but i only suggest that you dont have to click when you get to a cheak point :( taking you hand of the arrows gets a little anoying :P just a helpful tip! :)
 "Demons Took My Daughter"){kind=icon}
 "Great Dungeon in the Sky"){kind=icon}
 "My Tower Defense"){kind=icon}
 "Crash Test Launcher"){kind=icon}
 "Harry Quantum: TV Go Home"){kind=icon}
 "Wars of Monuments"){kind=icon}
 "Little Indian Warrior - Remix"){kind=icon}
 "This is the Only Level TOO"){kind=icon}
 "Big Pixel Zombies"){kind=icon}
 "Blockage"){kind=icon}
 "tomato Domino"){kind=icon}
 "DuckLife2: World Champion"){kind=icon}
 "Shoot the Stars"){kind=icon}
 "CellCraft"){kind=icon}
 "Jeff The Archery Master"){kind=icon}
 "Effing Worms"){kind=icon}
 "The Gun Game 2"){kind=icon}