First, let's get this out of the way: this really isn't that fast. It is fast in relation to And Justice For All, or, say, Black Sabbath's debut, but it's not as speedy as Reign in Blood, and nowhere near as speedy as, I dunno, Darkness Descends; nor does it feel as unhinged as a bunch of the early german thrash bands. Put it this way: I, a drone fan, Metallica fanboy and extremely casual thrash follower don't find it that fast or hard to comprehend. So please dudes, saying this is extremely fast is just embarrasing for everyone.
So with that point done, allow me to bring out a generalisation; it's usual japanese metal- a competent take on a genre, with excellent production values- bass is audible, a real nice guitar tone, very tight drumming. This is all fine and good but considering that this band's sole/main gimmick is that it is thrash as shit, I reckon this would be a fair bit better if it was recorded by South Americans. There's this Brazilian band called Wardeath who do a similar 'we are really fast!!' type thang, but whereas this record here is all crisply recorded, very on time, probably very pro tool'd up, Wardeath just go at it as crazily as possible, on time-ness and tuning be damned. It's something these guys could consider, for sure.
Comparisons with this random ass Brazilian band I mentioned can be extended beyond tempo, as well. Fastkill write some pretty decent riffs, for sure, but for the most part they aren't terribly amazing song writers, and Agony and Eternal Pain aside there's little in the way of extremely memorable stuff- it's fast, it's sorta vicious, but it's not amazing, y'know? It makes you bang your head, but that's because of the basic techniques that are being used, moreso than the stuff that is actually being written. Welp, Wardeath suffer a similar problem- they ain't exactly the best songwriters around- but they go at it with such conviction, such menace, that it works extremely well. Fastkill, not so much.
Sure, props are due to the nice mix of Slayer, Dark Angel and early Kreator here, it's not party thrash and that's cool and something I applaud. But it's not really that great, that's all I'm saying. It's sort of similar to the Dragonforce approach to power metal- speed isn't everything*! Go and check out Wardeath instead.
* This is a bit unfair to Dragonforce, who are a good deal faster than Fastkill.