of the circuit:  Rocket Riot WP7
I have one achievement left to get, the one where you use the triple shot and get three kills in one shot, it is incredibly difficult to get as you need to get the right power up then get to an area where you have enough enemies in clear view to use it.  Anyone have suggestions on the best level to do this?  I'm thinking the rugby riot level although I'm not certain it has enough enemies.