If you liked this game look for an old school pc game called Dark Omen. It is essentially an exact copy except Dark Omen is much more in depth with more troops, spells, and levels.
the last boss isn't really that hard, read some of the comments. This one helped me get through it on like the 10th try or so is all;
"In case any one needs it, safe spots for the last boss are: --Rapid fire small bullets - Hide in one of the "diamonds" on the right side, between the crossing streams. Move with your safe spot. --Crossing Small Bullet with Large bullet chaser - On the right hand side there is a recessed point that doesn't fire for this attack, 4th from the right. Hide just below it, just below the point where you start taking contact damage. Don't move until the attack is over. --Homing Missiles - I used avatar for Acydyk's strategy of moving slow along the bottom to clump the missiles, then shooting across above the missiles. Continue the loop. --Pulse - Just don't be under a point after it lights up. I stick to the points 7 to 8 from the right."
finally got the impossible! was sheriff with reg shotgun mk-10 4 slots: anti-armor3, accuracy3, damage2, leech3. Had noble with grav gun mk-6 1 slot: impact3; militia with grav gun mk-4 4 slots: leech2, impact3, damage3, damage2; and duelist with longbow mk-11 3 slots: auto fire3, fire rate3 x 2. set duelist to kill boss, others to fire at will. Duelist kinda sucked at fighting but needed him for negotiator and engineering skills! the villa is crucial, try and upgrade once every 10 levels or more if you have spare gold. Active is crucial too for more ap to forge weapons and other stuff. Some of it is luck, try and find the weapons with 4+ slots and always have a grail on you! Would have died twice without it on a suicide wave and dragon wave. Don't even try the impossible without having most of the badges, they help a lot. Good luck!
got extremely lucky with the impossible badge, one yellow "L" brick almost fell off on the right but was luckily saved! I'm thinking even placement is key as this time my tower swayed very little even at the end unlike most of my other attempts.
http://img.photobucket.com/albums/v471/danoodle/tower.jpg
 "The Grinns Tale"){kind=icon}
 "Hordes and Lords"){kind=icon}
 "Last Square Standing"){kind=icon}
 "Reactance"){kind=icon}
 "Burrito Bison"){kind=icon}
 "Flight"){kind=icon}
 "Elona Shooter"){kind=icon}
 "99 Bricks"){kind=icon}
 "Dream World"){kind=icon}
 "Castlewars"){kind=icon}
 "MARDEK RPG: Chapter 3"){kind=icon}
lol :D