Even Easier Way how to get All Badges Here are sample pic
http://s80.photobucket.com/albums/j169/deathmanelf/?action=view¤t=Chain.png
Start Along The Road then make it longest posible [U can see the patern]
It shoudl be completed around 20. wave.
Go Settings and set 200% Speed but leave wave timers as they are.
After that max last tower in chain and first in chain [POWER ONLY].
Then just put Red Tower [Rockets] to head and Max IT [Power Only]
After u got IR MIssile u can extend tail a bit along the road becouse u will never see creep again [and if so then u just losed game :P]
Upgrade Power from tail to head + Put some Power Exchange Buffers along so u can have really long chain [they come at round 110]
After u get aroun 22000000000 Dmg Link u should get a coffe and wait for ur Hard Badge
Good combo ?
Make longest laser chain possible max Head and Tail [Max power only for last and first tower in chain] Then put Missile tower at start and Max Power [u get super powered IR Missile Tower and u dont see creeps few hundred rounds from now on]