Click on a black button, then on the place that you want the tower to be placed. It will appear there. Note: You may only place 1 of each tower type. Snipers and Machine Guns shoot at your pointer. Quadros can be placed on the track, and shoot in 4 directions automatically. Quadros are currently the only towers that can be upgraded - click on it to upgrade (If it doesn't work, you have too little cash). This is based on Bloons Tower Defence. Go to www.ninjakiwi.com to play the original. This closely models the Drag Strip track, but you need to have a high rank to unlock it. For those that haven't played Bloons TD before, you need to pop the bloons in each level. The 'bloons ' are coloured balls that go along the track. If they reach the end, you lose lives! This is 'Apocalypse' mode, so there is a tiny break between each wave. Normally, you start the waves manually, but they come automatically. Coming up for Version 2: More towers. More waves. More enemies. Better display for money etc. More EPICNESS!
This is my first ever proper Scratch game. It took me a few hours worth of time to put together. Here is the URL for Version 2: http://scratch.mit.edu/projects/11385676/
