There's many things I like but also about the same amount of things I don't like about The Firstborn. These guys surely knew how to play their instruments and the ideas were bursting in these four fast-forward thrash tracks. However, the drums are way too loud for my taste (even for me as a drummer), especially during the parts with the double bass the rest of the music seems to be drowned by the sound of the drums. Nevertheless it's impressive work on the drums. Second thing I don't really like is the mix of the vocals, it's too far in the background in comparison to the instruments. So basically, drums are too loud, vocals too quiet.
This EP might not exactly be the most known piece of underground thrash, that's mostly because it isn't available anymore. It doesn't pop up on eBay and stuff that often either. If you should come across a copy in the future, don't hesitate to get it! Might be the last time you'll see it ..