It's pronounced "boob ass" because that's what it sounds like. And Slayer is about the most insulting name they could have given FL Slayer.
BUT! I will disagree with timaeus on one point... it isn't "not bad"... it is in fact fairly bad. But with some improved samples, maybe a guitar library you pay for or a live guitarist you ask to perform, you might be moving towards making some progress. It's a cover right now and that's not what OC ReMix is about.
A good starter drum library is Addictive Drums, but I saw decent pricing recently on Slate drums. The bottom line is if you want to make metal remixes, you will need to compromise in some area and have good samples and live performances. You can get away with using sequenced guitars like Shreddage, and maybe even sequenced bass like Trilian, but people can tell -- if you're forced to use too many sequenced instruments, you gotta make sure they are as high quality as humanly possible.
If possible, it'd be better to have live guitars, and sequence the rest but improve their sample quality a lot. You can get by with that kind of setup. Even outside of OCR, you will need to do this. This isn't purely OCR-based advice. Making these improvements will help you -everywhere- you post the music at. I do wish you the best of luck and hope to hear your future improvements and WIPs!