SeonR, Ha! I was having a tough time with the Circuit level - I was getting to the 19th/20th wave and running out of real estate on the map. Played it several times in sortof charge/slow retreat fashion keeping my one little guy (usually mortar guy) moving all the time, but the last wave or two would kill me. It's was so hard to get enough money to buy any troops on this level. I figured there's gotta be a better way to play this level than running my 1 guy around constantly spamming mortars (back and forth kindof like Space Invaders).
So I pulled up this videohttp://www.youtube.com/watch?v=jM6cvZ7qYJs
I saw you start and I was like "what is he doing" and "he's going to get over-run" and I saw you explode the whole map and I was like stunned. I had no idea what had happened. I had to rewind. I had no idea what the little cubes were or what they were for. I thought it was for bonus points or something similar. No idea they actually did something.