
The musical resemblance probably was intentional, and like a lot of video game companies, Capcom hoped to change it just enough to fly under the radar, or that the movie was so old by that point that the copyright wouldn't be enforced.
John Carmack, the original producer of Doom, once observed that Bobby Prince, the composer, was also a lawyer who knew how to change songs just enough to avoid copyright lawsuits. A lot of Doom II's tracks are basically instrumental covers of Alice in Chains, Slayer, Black Sabbath, and of course Pantera, from id's home state of Texas (The level 23 music, based on AiC's "Them Bones," is the most notorious example.)