In many RPGs, the PCs acquire new abilities pretty regularly. D&D is the classic example of this — level up, and you get a new ability (or at the very least, your saves go up, etc.) — but it’s true in points- or skill-based games, too.

But some powers (or feats, or abilities, or spells — they have different names in different games) have a lasting dramatic effect on the nature, scope and tone of the entire game. Sometimes they seem like little things at first (after all, the PCs get new abilities every level, right?), but they’re not.

These are the Big Little Things — world-altering, game-changing powers.

Regardless of game, system or genre, these powers will always have an immediate and dramatic effect on how the game is played. They’ll require you to adjust much of your thinking when you prep for sessions, choose opponents and decide on plotlines.

In short, they’ll change everything — in a good way, if you plan for it, or (potentially) in a bad way if you don’t.

So how do you handle them? Mainly just by keeping them in mind, and adjusting accordingly. With Big Little Things, the goal is not to nerf a PC’s cool new power.

The goal is to keep the game interesting for that player by providing new challenges, leaving in enough old challenges to make the power seem worthwhile, and adjusting gameplay to account for their new abilities.

Flight: Getting to the top of the castle wall, or onto the skyscraper’s roof, is no longer a challenge. Staying out of range of foes with no ranged attacks is child’s play (as is peppering them with bullets from the air). Ground-based hazards like swampy terrain and pit traps stop being obstacles.

At the same time, flying foes are now more interesting, as they can be fought on their own turf. Weather-based hazards (like gale-force winds) take on a new dimension, and disabling attacks — which can lead to nasty falls — become more of threat.

Invisibility: An invisible PC gains a tremendous advantage over foes who aren’t anticipating unseen attackers. Fortresses, terrorist camps and secret outposts suddenly become very easy to sneak into. A whole new world of spying opportunities opens up, particularly in a political campaign.

On the flipside, enemies who survive one encounter with an invisible PC will be prepared the second time around — and they’ll focus on that character. Depending on the campaign world, local officials may cast out, tail or otherwise harass a PC who is known to be able to turn himself invisible.

Death Effects: Often called “save or die” powers, death effects generally only have to overcome one barrier to instantly slay a target. This shifts the balance of every fight in the PCs’ favor, as one lucky roll can end even the most climactic battle on the spot. Lovingly-crafted NPCs that you intended to serve as nemeses throughout the campaign can be laid low by one assassin and a bit of planning.

On the other hand, death effects often aren’t much fun when they’re used against the PCs. A beloved character, the veteran of months (or years!) of adventures, misadventures and close calls, can just as easily be slain by a one-shot kill power. Without a counterbalance (like resurrection powers), death effects can really wreak havoc on a campaign.

Teleportation: The end of the dungeon is now just one spell away, as are the dark lord’s inner sanctum, the super villain’s secret lair and just about any other traditionally nigh-impregnable location in the world. Supply problems are a thing of the past, as a teleporter can always just pop home for more of whatever the party needs.

Star Trek features readily available teleportation in nearly every episode, and it works brilliantly. This is because Star Trek is structured to accomodate this ability, and because it’s not the focus of the show. There are also plenty of ways around it, just as there are with teleportation in your campaign — like clever foes with lead-lined lairs.

Resurrection: Once a party member can resurrect fellow PCs, death loses its sting. There may still be a penalty (as there is in D&D for the lower-level resurrection magics), but it’s almost certainly worth it. More than any other Big Little Thing, resurrection powers change the scope of the game from top to bottom. Characters can afford to be less cautious (which can be a good thing, encouraging cinematic play), and barring unusual circumstances, they’re effectively immortal.

Whether it’s in the PCs’ hands or not, the mere existence of resurrection powers changes the world. Rich NPCs no longer need to fear death. The corpses of particularly important people — generals, great leaders, famed adventurers — become prizes unto themselves. Depending on how common resurrection is, common folk (and not just peasants in a fantasy game, but the rank and file in any era) might fear it — and those who use it to return to life.

I’m sure I’ve forgotten something on this list — what did I miss? In your experience as a GM, what powers qualify as Big Little Things?