razieltnt wrote:without premium content?
sure
and without hero, try it out
I was doing those levels with all towers on HARD without bonuses mentioned above (only campaign mode)
Can You suggest any nice tactics with Bolin involved ?
I am doing the challenge with Bolin, campaign only for now and doing okay... I'm up to Lineria.
I find one of the best strategies with Bolin is to use him thus:
1. Its all about the mines! Have him in the back to start off, laying mines near the exit... This especially helps on levels with many wolfs and spiders.
2. His gun is great at killing gargoyles. By level 3 or so he can one shot them. This, plus reinforcements that can throw spears will hold off flying waves until Big Bertha or Tesla can help out. Also his gun has pretty far range. Basically I keep him near the exit. The less he moves and fights, the more he shoots and the more mines he lays down... Keep him still whenever you can (makes him good for those who like to play more hands-off with their heroes).
3. I rarely use him to fight one on one. I treat him as a ranged hero... Laying mines, shooting flying things (and other enemies, too), and his oil slick helps a lot on levels with rotten husks and graveyards.. A slow group of Tainted Treants and Swamp Things gives Teslas a few more shots!
4. Unlike other ranged heroes, if you see a proble coming and Bolin can walk fast enough, he can also tank until your reign of fire recharges.
Yupikayey! 
