Objective: Survive 10 waves
This level I found to be simple enough. Build and upgrade two rocket towers like the picture below. When you can, then upgrade your splash tower and scout tower. The splash tower will hurt the enemies enough so the rocket towers are then a one shot kill.
Your Guide to: Tower Defense by COM2US 
AVR
24/07/2012 at 12:11
Easy hard finish – forget the rocket towers. upgrade the raised scout tower fully then build s second one right below it and fully upgrade it. then take out the pink blobs and use resources to upgrade the splash tower. once you have enough resources build another scout tower on the middle island at the bottom of the screen and fully upgrade when possible. and finally build a 3rd scout tower on the sinlge island to the right at the bottom of the screen and you should have that fully upgraded by the final wave. Win. 1268 points +1600 (8/8) +1865 (02’14″06) *2 hard = 9466