I'm not a real TD expert, so at first I thought it was too hard and unbalanced (the first tries I managed to survive at most 4 minutes...).
But then after reading the other comments I tried a strategy and got to 16:56.
Well, if it made me try to do better and better it surely means this game is fun! I'll definitely try to beat the 16:30 wave...
I'm impressed at how many items are in this game, great work!
Here are some constructive critics, just because I think this game has good potential and there are just a few things (IMHO) to make it perfect. Some are just my obsession for the interface, so don't take them too seriously: * I hate when the seconds are not padded in a time display, so, in the clock at the bottom right corner, 0:06 would be better than 0:6 * items creation buttons in the left side have on hover effect even if I don't have enough money to buy it. It's good only if you make a sound like a buzz if I click on it and I can't afford it * a tooltip on the items creation button would be extremely helpful, with that it wouldn't be necessary to read your game description. Something like: `Seraph: needs Temple. Health: 150. Range: 75. Speed: 200. Damage: 250/4s.` * when I'm positioning a building it would be good to have some green and red areas to let me know where I can put it and also a circle around the dragged building to identify the area that it will occupy * some simple sounds would have been good, even generated by [ChipTone](http://sfbgames.com/chiptone/), at least when my building explode * a better lose screen, so I can restart without refreshing the page (I played the web version)