Best TD so far..
sry, my english is a little bad..
Anyway I like the concept of upgrading and building on the map, the graphics are fair, gameplay also.. However I haven't noticed that upgrading units are actually better than the non-upgraded ones, but spending on unlocking new units is a nice concept. Also the I personally think that the air enemy units are a bit too strong/fast/resistant to the archers, but that's my opinion.. It would be great to add an option of setting targets for your units (example: nearest enemy, weakest enemy, air units, ground units ecc).. Perhaps I haven't seen that option.. Anyway great but not perfect TD game.. Keep up the great effort ;)