To be perfectly honest...almost none of these guys bothered me, they each had a counter.
Shadow archers: bring your barracks men as far back as possible and allow your towers to kill them.
Troll Chieftans: Use fully upgraded reinforcements at range distance to do pretty significant damage with spears...plus towers.
Demon Lords: just use a magic tower with avada kadavra...they always come first in the wave and that means you just one shot your hardest enemy.
The list goes on, but the ONE unit that did somewhat bother me was the rocket air dudes. The counter to them is to have a tower that hits air close to the spawn point...but sometimes you don't know when they're coming and it can be a real pain if they get to your towers while still having the speed boost. They don't stop for your units and they move fast as hell during their sprint. Thus, they are the only units I disliked in KR.
And yes, I have beaten the entire game on normal with doing each level on heroic and iron man, so you should understand that when I say EVERY OTHER unit is easy, it's true.
To beat the Rocket Riders you have to have fully upgraded mage towers, 'cause that gives them a slow spell. So when a Mage hits a Rider, he doesn't blast away. At least, it worked for me.
The Rocket Riders are horrible because they start running exactly after i first hit them.The Dark slayers have lots of health and they aren't affected so muc by the meteor strike.Without mages,aggainst them i am dead.The ogres are almost invincible once they got any shaman around them.
I have all the stars, including bonus content. I almost have all the achievements - right now I'm finishing the Heroic levels on hard difficulty. I thought Kingdom Rush was very easy, so long as you think about what you need before you throw a whole bunch of stuff down and end up regretting it later. It also helps to do a an analytic play prior to beating the level so you know what the level is like.
