The cost of dwarven ballista towers does not increase as you place more of them. The units themselves aren’t particularly good, even at high levels.
Fighters are okay at higher levels, and I believe wizards supprt them preferentially. I prefer paladins, but they’re expensive.
The expansion content doesn’t change the core gameplay that much, although the sorceror spells are nice during the late game, and the magic bazaar potions greatly improve hero survivability.
As the dragon came the second time all my four Solarii attacked it, and the dragon couldn’t hit them often enough to kill them before they drank healing potions. They all just kept hitting on the dragon and increased in level and as their level went up it became harder and harder for the dragon to hit them. What resulted was a combat where none of the combatants could hit the other. As the dragon was busy fighting it never hit the trigger that would make it leave after a predetermined time so I was stuck watching all my heroes battle endlessly against a dragon thta coudln’t hit them, and which they couldn’t hurt. All the while increasing in levels. By the time I gave up My solarii had just hit lvl 20, and the Dragon had been fighting them for 6-7 days.
The only “solution” I could see to this was to restart and, when my solarii started fighting the dragon, kill them myself with magic before they became too powerful. Then the dragon would rampage for a day and leaveand I could hire new heroes and complete the mission
The scrolling speed is unplayably fast on a modern machine
I’m playing with a nearly 2 year old rig. Windows XP P4 1.8, 512 Ram, GeForce Ti200 128 MByte. I haven’t had any problems with the scrolling. It is a bit jumpy sometimes but only marginally so. Maybe there is some setting that you can adjust for scroll speed. Haven’t looked myself. The animations all play pretty smoothly even with a full town and dozens of heros.