Flash Element TD 2

My latest tower defense game addiction comes in the form of Flash Element TD 2.
As you know from previous posts I like my Tower Defense games to be a good challenge to complete. A game that's frustrating but keeps you coming back to try on new strategies.

So when I first heard about Flash Element TD 2 I was chomping at the bit to play it. Part 1 was one of the first online Flash tower defense games and its still one of the best today. The 2nd installment ups the ante on the cute graphics and sounds. The new element towers are cool and upgrade well.
But the biggest innovation comes in the form of the elements you need to protect. The elements sit at the end of the usual path enemies travel down and once they reach them they pick them up and begin traveling back the way they came. If they escape with all the elements its game over!

I really like this game but here's my beef: level design.
There are only 3 levels. And only the first 2 are free to play. (Easy) is way too easy. Next level is (Harder) and yes its insanely harder. I can't beat it for the life of me. My highest score is 34864. I can't figure out what I'm doing wrong? Upgrades get expensive and it seems powerful enemies give out the same amount of money as the enemies from the first level???

Well at least this time I won't go spoil my frustration by checking out a youtube.com video. ;)