All those joyless souls lamenting the death of rock really should give Download a try. Despite invariably being plagued by hideous weather, this year, enthusiasm for three days of big riffs and shouting appears to be at an all-time high. You can see it in the riotous response that Clutch receive on the main stage on Friday. Practically unknown outside left-field rock circles, the Maryland quartet have steadily become one of the great rock’n’roll bands of the modern age. They are also far funkier than they look: even without the studio version’s blaring horns, In Walks Barbarella turns previously raucous mosh pits into a mud-caked episode of Soul Train, much to hirsute frontman Neil Fallon’s delight.

Rock’s old guard are out in force, too. David Coverdale is still lascivious charm personified as Whitesnake thunder through the hits and a couple of sparky new songs. “The sun’s out!” bellows the Cov, beaming from ear to ear and looking like some fabulously wealthy LA grandma. Much less diverting is Slash, whose solo material is phenomenally dull. A perfunctory canter through Guns N’ Roses’ Nightrain aside, it’s a struggle to pick out a memorable tune or genuinely dynamic moment. Fortunately, there’s no disputing Def Leppard’s headlining prowess. Playing the all-conquering Hysteria in its entirety, they sound immaculate and vastly more engaged and spirited than they did last time they topped the bill here in 2011. Let’s Get Rocked is still horrid, however.

Saturday is a feast of bombast and exuberance. Everyone’s throwing the kitchen sink at it, from satanic extremists Behemoth’s wildly subversive conquering of the main stage to Skindred’s remorselessly uplifting ragga-metal riot. Quite how South African hip-hop group Die Antwoord fit into all of this is anyone’s guess – and they look pretty confused about it themselves – but the pounding EDM insanity draws an enormous crowd and everyone seems to know the words to Fatty Boom Boom and I Fink U Freeky.

Anointed kings of the Donington turf ... Corey Taylor of Slipknot on stage at Download. Photograph: Katja Ogrin/Redferns

In truth, the whole day is really just one big buildup towards Slipknot’s set. It’s the fourth time the Iowans have headlined at Download, but they’ve never sounded more pissed-off or antisocial. New songs All Out Life and Unsainted are greeted like classics and the size of the crowd alone confirms that they are anointed kings of the Donington turf.

As diverse as it is, Sunday at Download is Slayer day, as the thrash legends play what is supposedly their final UK show. Earlier in the day, Swedish veterans Amon Amarth turn Download into a giant Viking piss-up and, after scoring a No 1 album in Germany recently, they are destined to be much higher up the bill next time – Twilight of the Thunder God is an absolutely fantastic heavy metal song. Bringing Download to a wilfully obtuse close, Tool’s long-awaited return as headliners is as hypnotic (two new songs are on first listen, laudably trippy) and contrary (the main stage’s big screens have been turned off) as fans will have hoped. But nothing can compete with the fire, fury and precision conjured by second-stage headliners Slayer as they rip through 90 minutes of certified hymns to the dark side. As the final grim strains of Angel of Death echo across the mud, it’s hard to imagine metal ever being this intense again.