Hm. Come to think of it, the first riff in both of those songs really are kinda similar.
But the Breeding Death EP is/was a tribute to 'old school death metal'. Morbid Angel's first album kind of qualifies as that. I haven't listened to Altars of Madness in a good while, so I can't remember all of the riffs (I worked out the Breeding Death EP not long ago, so the riffs are fresh in my noggin).