Demigod is fun, and more than any other character I play TB because he rocks.
Ice mode is far superior to fire mode, though, and I've started playing games where I never switch to fire mode, except to get the mana regen boost and the damage boost from switching back.
Deep freeze bugs some times and I don't understand why. Occasionally in the heat of battle, I'll press 3 (for deep freeze) and target a bad guy. But the Deep Freeze doesn't take a TB just stands there. Intrinsically, I immediately repeat the other and try Deep Freeze again. The bug is that Deep Freeze won't work until I give a move order then try it after that. It shouldn't be like that.
Another bug is I had a large 5v5 panthenon game last night. About every 20 minutes the game would suffer a 2 minute long lag spike... for 2 minutes the game would freeze, the screen would turn a monotone grey, it looks like the game engine crashed.... but I waited it out all 3 times and 2 minutes later the game resumed as if there had never been any hiccup. Totally kills the pace of the game imo.
Lastly is another balance remark. The level 20 cap sucks. I understand the usefulness is having only 20 skill points. This makes sense, but the level 20 cap is a huge burden. I was playing in previously mentioned 5v5. I was 5 levels ahead of everybody else when I reached level 20 because I had been kicking ***, including a 15 kill streak. I ended up amassing 30,000 gold. I got the +120 attack sword and the God Plate armor. I was ripping through enemy Demigods. The problem was the game was on forts (eg, destroy all 5 enemy forts to win). 2 enemy forts remained, and whenever I'd attack either of them, 4-5 enemy demis would tele scroll there to fight me off. Seeing as I stopped leveling and they had continued, they were just trying to stall me.... and it worked. I managed to kill 1 more fort, but not both of them, before all my enemies reached levels 19/20. Despite being far better than anyone on the opposing team, I still lost the game because of the level cap. Allow more levels, just don't give skill points after level 20.
Oh, a favor points are bugged too. I was saving up favor points for an expensive item. When my favor point count reached around 600, at the start of the next game I had only 150. The favor point count resets itself. 
Achievements also don't work. At least twice I have been awarded an achievement in-game, the big announcement came up, fellow players even made comments congratulating me. I open impulse, go to 'achievements' and 'You have no unlocked and achievements yet.' Fabulous.