Testament released First Strike is Deadly today, 1987.

I heard, Over The Wall, and was hooked.

You mean The Legacy?

Oh yeah, I mixed the rerelease up with it, haven't finished my coffee.

This might be the best thrash debut ever, at least in the secular realm. Not a bad song on it. I love most of their stuff, but I don’t think they ever topped this one.

Practice is my favorite but it's really hard to pick their best.

Practice got me into them, and I dig it. I just think the riffs are a bit better on The Legacy.

This is in my very top echelon of thrash metal.

The power of it is in the mix of songwriting from Zetro/Skolnick/Ramirez/Peterson, and the top notch thrash vocals of Billy.

Skolnick hadn't taken over the band and run them into the ground yet.  Chuck wasn't writing lyrics.  Also, they weren't trying to be commercial.  It was purely inspired by Horror movies and early Metallica and Slayer with Skolnick levelling up his soloing after the Legacy demo.

This was an extraordinary album, because it had memorable songs and melodies that were very interesting.  
I'm not so much into thrash these days but an album like this, I can still put on and enjoy.  

Looking at the other thrash albums released in 1987, The Legacy was head and shoulders above the rest.  
Although there were some other thrash / extreme metal albums I liked such as Voivod - Killing Technology, Sodom - Persecution Mania, Celtic Frost - Into The Pandemonium, and Heathen - Breaking The Silence.