If DOOM Eternal was the kick up the arse the gaming industry needed towards the start of this year, DOOM Eternal: The Ancient Gods - Part One will leave those buttocks raw. The Slayer himself has returned with the first instalment in a new expansion so utterly relentless that a rude awakening is in order for even those who reckon they mastered the base game. At its heart, this is much more DOOM Eternal. However, given the outstanding quality of that particular title, an even tougher take on what we've come to know and love is an irrefutable proposition.

Due to the DLC's naming convention, there may be some assumptions floating about suggesting this is a fairly short undertaking. And while there are just three new missions to work through, they're by no means lacking in content. Each packing brand new environments and secrets, it'll take you a good six to seven hours to roll credits. This is a meaty package despite the narrative linking together each and every combat arena ending on a cliff-hanger.

Speaking of which, there is a story to DOOM Eternal, isn't there? We always saw it as nothing more than just another reason to slaughter the legions of hell, and the case is very much the same with The Ancient Gods. Following the events of the base game, an imbalance of power in the universe has forced the evil infantries down under to make one more claim for top spot. Or something like that.

Yeah, there are some curveballs along the way, but it's probably the least important aspect as far as the DOOM franchise is concerned. Intense, fast-paced gameplay is king and Part One remains true to that philosophy. The Texas-based studio hasn't messed with what works in the months since DOOM Eternal's launch, meaning the DLC is still all about diving headfirst into the action. Glory Kills reward health, the Flame Belch drops armour when enemies set on fire are defeated, and the chainsaw spawns ammo for all your weapons after tearing through flesh. That satisfying loop hasn't been tinkered with one bit.

If anything, that's actually a through-line you could make through virtually every element the DLC encompasses. Alongside minor complaints about not having enough ammo to see an encounter through to its conclusion, platforming sections were also a source of criticism. They are back and better than ever — forcing you to properly analyse your surroundings and come up with a way of progressing. They can become slightly tedious on your third or fourth attempt, but for the most part, platforming continues to be a bundle of fun. id Software has doubled down on its vision for DOOM and the series is all the better for it.

New locations help to give those tried and true mechanics a breath of fresh air and the expansion does not disappoint in this respect. Kicking things off on a gigantic oil rig before heading underwater to its underground lair, Part One is packed full of impressive settings that deserve a second or two of appreciation. They even introduce new and interesting ways of moving a fight about a larger area.

As alluded to, though, it's actually the overall difficulty level that feels like the biggest game-changer when The Ancient Gods is compared to the base experience. If you haven't played the game since its March release, expect the first half an hour or so to revolve around dying over and over again. The DLC isn't afraid to throw the kitchen sink at you from the word go and that could lead you to lowering the difficulty, at least for starters — don't worry, we committed the very same sin. But even when you do get up to speed, this expansion still doesn’t pull any punches.

The Ancient Gods is persistent in its adherence to throwing waves upon waves of the title's most resilient enemies at you. And then doing it all over again just a few minutes later. It almost borders on a sort of Bullet Hell take on DOOM Eternal that absolutely never lets up. Although, that also gives way to unfair difficulty spikes. It feels like too much sometimes. A boss fight in the second level is miserable, simply put, while some combat arenas are so overwhelming that we were begging for mercy. Sure, some players will revel in this sort of encounter design, but we're confident the average user could seriously struggle here. And that's even on the easiest difficulty setting (yes, we tried it).

If that wasn't enough, hell's legions have also been bolstered by three new enemy types. Each taking centre stage in the three different levels, they range from turrets and temporarily invulnerable harpies through to a spirit that possesses fellow monsters to improve their damage output and health pool. All of them have a unique trait, meaning you'll have to quickly learn their weakness and incorporate it into the dance between offensive and defensive output. It's a bit of a shame then that the Doom Slayer doesn't gain access to any new weapons for himself then throughout Part One of the post-launch campaign.

At least there aren't actually fewer guns, though — a fate that has befallen the music. After the public fallout between id Software and Mick Gordon, the composer did not return to write the DLC's soundtrack and it absolutely shows. In his place is a set of largely generic tracks that feel like the sort of tunes a tribute band would put out if they were trying to emulate their favourite act with new songs. It's all rather forgettable, unfortunately.

Conclusion

DOOM Eternal: The Ancient Gods - Part One is so much more of the PS4's best first-person shooter. It doesn't do anything dramatically different from the base game, rather letting its phenomenal gameplay loop revel in new environments and against new enemies. Difficulty spikes present more problems than we'd like, though, to the point where casual players might feel like giving up. Nevertheless, bring on Part Two.