I have no idea how fast it is running for you in DOSBox, but IMO compared to other BUILD games it feels faster and harder.
On that topic: enemies feel smarter and more aggressive, which I think is mostly achieved by having them chase you down promptly. Their weapons also bite; cultists carry the same kinds of weapon you do (i.e. shotgun, tommy gun, dynamite), and some monsters combine ranged and melee attacks.
