Just beat it on hard with $300k and 19 lives and I only got 67K points.. how are they getting MILLIONS of points? This is before the interest on the last level that bumped me up.. I didn't realize I got 2 halos I could have bumped my interest rate up to 35% but still that wouldn't have gotten me millions of points.. what are they doing to get such high scores
Cheating, basically. Using the arrow tower exploit in the beginning to inflate their starting gold, and throughout the middle taking advantage of it by selling all upgraded arrow towers to maximize their gold. After 40 levels of doing that, they're holding onto millions of gold already, and the interest is causing their score to be inflated artificially.
Divide your interest by 5, that's how much of your score for that level came from interest.
Hopefully this exploit will be fixed...but in the meantime, it does mean quite a bit of fun. I used it to get enough interest to have an Easy battlefield filled up with fully upgraded Magic towers. That was funny

The politicians had no chance...
Since we have the attention of the developers here, and there isn't an official TapJoy.com yet, I figured I could post suggestions here...
1. iPhone's got a hefty processor, but I notice a lot of lag when there's a lot of activity on the screen (e.g. enemies all along the path, and towers everywhere shooting at them) - can this be tweaked and improved at all? It drives me nuts
2. I noticed if I close the app at the "Congratulations, you dominated TapDefense" screen, and try to reenter it, the game crashes and I need to reboot the phone to get back. Would it be because, perhaps, it's attempting to "save" a finished game, and then having a problem getting back to it?
3. Building a mass number of towers is somewhat tedious, especially to upgrade them. Can we get an "Upgrade" and/or "Another" button next to "Finalize"? the Another button being a duplicate of the tower that was just built...including any upgrades.
4. If I have an excess of towers on hand, and strong enemies, but more than enough power to kill each one with one shot, all of the towers still fire at the front-most enemy, killing him 3 times over. Could the tower AI be adjusted to account for what else is shooting at it, and if it's going to be dead, pick the next enemy?
5. Internet access is a little spotty for me. If I don't have internet access, but I finish a killer game, I'm out of luck unless I just don't use the phone at all until I get back home to get a signal with my wifi. Could local scores be saved to sync to the network later?
6. An extra "Endless" level might be fun as an optional bonus after the Politicians. It ends when one reaches Heaven, doesn't affect your ending life count, and gives you a chance to increase your final score. The enemies should be 10,000 strength politician-like (fast) and resist everything, so as to give a large bounty in your gold and your score when killed.
7. Enemies that resist ice or water shouldn't be slowed down by them in the hard difficulty level.
8. Once you fix the arrow tower exploit, clear the high score lists (both local and network)
9. Put in an "Insane" mode that you can unlock when you beat Easy, Medium, and Hard, give them 10,000 gold to start with, all towers available, and make it so they can spend that gold and build those towers only in the first level.
10. Probably way out of left field here, but maybe make a mode or a game where YOU are the creatures trying to get past the tower defenses.
I'd pay a couple dollars for a game with a lot of these suggestions. I'd bet a lot of other people would, too. I'm a developer and I'd be willing to help. I love these kinds of games as much as you guys do