New strats such as spamming Dark Army towers to buff your heroes and using Rocket Gunners with AoE, since the TG I used previously wasn't hitting Goregrind. And another thing: buy the top AW Death Ray after the fight begins, because otherwise they will instantly waste it without getting bonus damage from the Arborean Emissary debuff.

Yet, this time can be improved by having two Kosmyr spells available (I miscalculated, as you can see) and actually putting your Rocket Gunners to shoot Goregrind! I figured out that the Dragons were dying to the acid from those last enemies so now I put they a bit far (and in a way that they won't get stomped by Goregrind). Bonus fact: Goregrind got buffed recently and received 25% armor, so that's another point for using Rocket Gunners, since their AoE skill also removes a bit of armor.

Despite the fact that this level still has room for improvement, I am moving on from it now, because my goal was sub 13 minutes and that's achieved. Let someone just overtake my position (which is something very easy to do). We evolved, it's not Boregrind anymore... It's Gonegrind.