Turn one, his magic didn't do a whole lot, especially because the Horrors were out of range with their 18" magic missile (D6+1 Strength D6+1 hits. . .that goes off on a 4+?), and with six Dispel Dice I was sittin' pretty. His Lord of Change did manage to miscast and wound himself. Sorry to say it wasn't the last time my opponent would shoot himself in the foot. Anyway, my first shooting phase saw an end of that Lord of Change, though it did take a stone thrower and two bolt throwers. Next turn he miscasted again. . .and again. Yes. Twice, and I'm pretty sure one of those casting attempts was with two dice. Long story short, he killed nine of his own Horrors.
The game was fairly even from there on out. I failed again and again to do any serious damage to his units of Flamers (my organ gun misfired turn two and couldn't fire turn three. . .turn four it got charged and destroyed), which managed to take out both bolt throwers and my stone thrower. I failed horribly with a unit of warriors and BSB against a unit of Horrors, ran, rallied and ran again. By the time my Longbeards and Hammerers managed to get into the fight, the two units of Horrors they were fighting were already well under strength, and thus weren't much of a challenge. What I was surprised by was the fact that he managed to do a great deal of damage to me, and very little of it was in close combat! Really, the biggest loss was when my warriors and thane failed to kill ANY horrors, lost combat by a lot and took off. That definitely lost me a lot of points, and also gave him two standards.
Looking back on the game, with my current loadout of five war machines, I'm just not that concerned with Tzeentch Daemons. The units of Horrors have to get close to be really effective, and my shooting can (hopefully) handle the Lord of Change by then, which drops my opponent's dice pool by four. Obviously my opponent had some bad rolls, so I'd like to test my mettle against him (or another Tzeentch Daemon player) again and see how it goes.
I have found that the Tzeentch power die of doom lists seem to be fundamentally flawed. For starters, the Horror units have shorter-ranged spells. Their nastiest spellcasters (Fateweaver and Lords of Change in general) are all high-cost Large Targets that aren't the greatest in close combat. Horrors themselves are awful in close combat. And lastly, there's always that threat of miscast. Honestly, the worst Daemon lists to tackle have been, in my limited experience, Skittles lists. . .y'know, a little bit of every color. Anyway, it'll be interesting to see what kind of turnout, as far as army selection, we get at our upcoming tournament on May 1st.