Remember when buying a game didn't feel like a guarantee of seeing the ending? There are still hard games out there, Dark Souls flying the flag most recently, but increasingly, the challenge has dripped out or at least softened, often leading to sadly wasted opportunities. What would Skyrim be like, for instance, if its ice and snow wasn't simply cosmetic, but actually punished you for going mountain climbing in your underpants?

With a quick mod—Frostfall in this case—you're forced to dress up warm before facing the elements, and things become much more interesting. That's just one example, and over the next couple of pages you'll find plenty more. These aren't mods that just do something cheap like double your enemy's hit-points, they're full rebalances and total conversions. Face their challenge, and they'll reward you with both a whole new experience and the satisfaction of going above and beyond the call of duty.

Realism Overhaul

Game: Kerbal Space Program

Link: Kerbal forums

Kerbal Space Program is not an easy game to begin with, and the addition of any extra manageable parameters adds only more complexity to the brilliant flying sim. The realism overhaul wasn’t intended to create a punishing experience, it merely brings a few things in the game in-line with the real world. Solar panels are lighter, for example, but produce far less power. Cockpits and components that weigh the same as their real world counterparts, and engine propellants are more accurately simulated. The fact that all these changes make the game seem new and incredibly hard? Well, that’s rocket science for you. It’s also a great baseline for other mods, like the punishing Deadly Reentry mod.

Frostfall

Game: The Elder Scrolls V: Skyrim

Link: Nexusmods

Frostfall stands out among survival mods for complementing the open-world game underneath and not just demanding you stare at a temperature gauge and eat a deer every few minutes. Skyrim’s blizzards will kill you. Nighttime will kill you. The water will kill you faster than you can say, “Rose, make room on the bloody raft!” Big deal, right? All survival games do that. Frostfall alters how you understand the world, forcing you to find crossing points, plan your excursions and select gear based on more than its stab resistance. Simple quests become scenes from The Revenant. In the unlikely event Frostfall doesn’t make a human-sized ice lolly out of you, you’ll feel like a true Nord.

Infection Mode

Game: The Witcher 3

Link: Nexusmods

Zombie outbreaks are easy to handle if you catch them early, as you’ll find out if you install Infection Mode for The Witcher 3. The mod summons a Devourer, who you can kill immediately if you choose. If the Devourer attacks a villager, they become a Devourer too. Anyone they attack will join the Devourer legion, even children. The results are quickly horrifying. Go for a walk for a short while and return to the region for an enormous fight, or let one loose in Novigrad and watch the nightmare spread.

I Am Legion

Game: Dying Light

Link: Nexusmods

Day is night and night is day for Dying Light’s breed of zombies. In sunlight they plod around in small circles, not really paying attention. By night they suddenly become a lot more frisky. The circadian difficulty loop is a key part of the game, giving you the chance to scavenge during daylight hours and hold up at night in your favourite safehouse. I Am Legion disrupts all that. Zombies are more lively by day, and there are more of them, while a reduction in bandit numbers means choked access to vital resources like bullets and weapons. More than this, the mod transforms the tone of the game. Suddenly it feels like a true fight for survival.

Motion Tracker Remover

Game: Alien: Isolation

Link: ModDB

The motion tracker is your best friend aboard the Sevastopol. Guns immediately draw the attention of the bullet-proof monster, so until you get a flamethrower, there’s very little standing between you and brutal slaughter. The motion tracker is a little green beacon of light in a world of shadows and fangs, which only makes it crueller when this mod snatches that away from you. With a broken tracker you're forced to rely on your senses—headphones are recommended—if you want to make it to the next room alive. If you eventually get the hang of that, consider installing Unpredictable Alien at the same time, which tweaks the frequency at which the Alien chooses to roam in different areas.