very fun except for a few things...
The game was quite fun, very reminiscent of UMS tower defense maps in Warcraft 3. You got the basic tower, the ice tower, the poison tower, and the fire tower, but not the lightning tower (which is definitely *not* missed!). and the overlapping slow... nice. The concept is clean, the pathing is perfect, the sprites all look great, upgrading is nice (my favorite TDs were the ones with upgradeable towers), hotkeys are perfect. Very good all around. This is one of the best concepts for Defence games so far. I really like the fact that the stuff you buy actually hurts the enemies instead of just sitting there looking like it does (IE: the cannons in D-Fence, the archers in Defend your Castle, the gunners and archers in the Demonic Defence series), and you can see *who* they're attacking. Very nice. !HOWEVER! There are some issues that really bugged me:
At times, the game got very very lagged. At that point, it became *extremely* difficult to select things. In fact, in many cases, it was impossible, and towers that needed to be recycled couldn't be because I couldn't select them, then changing screens took a long time. For some levels, there were just way too many enemies. Perhaps instead of doing it with tons more enemies, you could just user fewer, but stronger enemies?
No AOE attacks?! The best thing about the ice tower was its AOE effect! As it is now, it seems to only be able to hit one enemy at a time, and since it attacks so slowly and stays on that target until it leaves range, it's not all that useful. The same is true of the poison tower, only it's slower and almost 3 times as expensive. So, the ice tower should be AOE, if that's possible. If not, then it should only attack enemies that haven't been slowed. The poison tower should do that in any case, and it should attack significantly faster, especially for the huge price.
Fire towers... well, the fire towers are kinda nice (since they do the most damage, and have nice effects), but I remember those almost always being AOE at higher levels (not in all TDs, of course). I guess that might require a lot more processing, because you'd have to determine what enemies are within some distance from the attacked enemy, and I can't really imagine any efficient algorithm for that (unless flash provides you with one already?). Otherwise, it seems to be pretty good.
The one thing that bothered me most was the elemental immune enemies. I would have what I thought was a nice tower setup, then early on, I'd run into stone immune guys. Stone towers were all I could afford besides the really slow ice towers. So I lose a lot of HP. That was lame. Then later one, I ran into fire-immune guys after taking a while to upgrade 4 fire towers to max, supported by an ice and poison tower...and I'm screwed. The poison and ice towers attack so slowly and do so little damage compared to fire. I had to recycle everything and set up stone elsewhere, which, even fully upgraded, did so little damage they just wandered past with minor scratches. That was lame too. So, elemental immune types should just be removed altogether. When they came in, it just broke the game for me. It stopped being fun because I couldn't do anything about them.
Other than those few problems (which I think are all very fixable), I *love* this game. As others have suggested, more maps! Maybe have some more complicated pathing with more intersections. More upgrade levels too! Maybe have the fairy do something...?