DOOM Eternal is all about having the right tool for the job. But some tools are more essential than others. That's the Heavy Cannon.
The only real main criticism I had with DOOM's 2016 reboot, and I don't know that it's a criticism per se, is that some weapons were a little too effective. Every classic shooter kind of falls into that trap: one gun is just a little too versatile, the default instead of the fallback.
And that was usually the super shotgun. DOOM Eternal does a better job of forcing you to switch things up, not to mention the balance between the need for ammo through chainsaw kills, health from glory killing basic zombies, using flame belch on grouped enemies for armour and zoning out with grenades.
But there's still one gun that is too versatile, too essential not to be considered the best. And you get it right at the start of the game.
As soon as you have the ability to unlock precision bolts for the Heavy Cannon, you absolutely should. Because while there are specific weapons and tools for dealing with zoning enemies out - the ice bomb in particular - the actual zoning ability you have in DOOM Eternal is the capacity to remove ranged attacks from other enemies.
In other words: the faster you can disable ranged attacks from regulars like the Arachnotron, Mancubus, Revenant and more, the more room you'll have to dodge in firefights.
What makes the Heavy Cannon so versatile is that there's no drop off in distance. Plenty of games, often for balance reasons, will reduce the damage of a bullet the further away the target is. They might also factor in bullet drop.
DOOM does none of that, which is fantastic. It means two things. Firstly, if you're coming into a firefight from a long distance away, you can already mitigate the damage from the first wave by picking off Revenant rockets missiles and the like without any risk. Secondly, it also means that when you're buying time with dashes or super jumps - and you should really learn how to super jump - you can buy an extra second or two upon landing, since any enemy hit in their weak spot will often stagger for a brief moment.
That's especially important when you started getting rushed more often. Getting rushed not only limits the space you have to dodge, but it also forces you into spaces you don't really want to be. If you're forced to dash into a couple of zombies, or a group of enemies, and you haven't dealt with those long range rockets or missiles, you're going to have to resort to glory kills and chainsaw attacks immediately.
Ideally, you'd want to glory kill a demon that's on their own, so you're always running around, or away, from the main pack of enemies. The heavy cannon helps there too: you can even just slowly tap the primary fire until a regular zombie can be glory killed. It's not the fastest way of killing them, but you can do it from range and the distance you get from a glory kill can often save you from reloading a checkpoint.
Also, as a nice bonus: the Heavy Cannon's precision bolt goes through enemies. If you're shooting a basic demon in the head, it'll pass through and have a crack at foes on the way through. It's not a magic missile or anything that powerful. But it does mean you can double dash out of a situation, turn around, fire a single shot and genuinely clean up some of the basic mobs quickly without jumping back in and getting surrounded.
DOOM Eternal tells you from the outset to keep moving, and you'll be dead within seconds if you don't. But the game doesn't give you all the tools you need to best survive, at least not openly. One of the best tricks in the game is the ability to launch yourself into the air, both as a way for getting out of tight spots and also surpassing some of the more annoying jumping puzzles. Here's how you do it.
You can't, of course, go through the whole game relying on the Heavy Cannon. DOOM Eternal is designed to force you to switch it up, through scarcity of ammo and the variety of enemies. But getting comfy with the heavy cannon isn't just a neat trait. It's essential for the game's higher difficulties, particularly Ultra Violence and Nightmare.
And flick shotting a demon's weak spot isn't just fun. It's quintessential DOOM, really.