In one area of the original Catacombs 3D game my computer starts to chug for some reason. Through the portal of Slime when you encounter a hallway full of locked doors it slows down so much as to render it almost unplayable. Anybody know a workaround or have the same problem?

Ctrl + F12 will increase DOSBox's cycles, making the game run smoother. Just keep pressing until the game smooths out.