Battlespire works fine for me in 0.65. At least the intro video, character generation and the beginning of the first level. This is after installing the Battlespire patch and ripping the CD to a bin/cue image and mount it with IMGMOUNT.
Wierd thing, thought, is that the game only detects "Warning: 31M RAM + Swap detected" in the beginning and not more even if DOSBox is configured for 63MB. While running in DOS on a real machine with 64MB, it will say something like "Good: 55+ RAM and swap detected".
I manage to run it with 45,000 cycles on the dynamic core on my AMD 3500+ which is somewhat playable with the low resolution and small game screen. I reckon it would be quite unplayable on a slower CPU.