SULFUR Endless Mode Guide: Perk Cards and Long-Run Tips

In SULFUR endless mode, every level-up gives you a choice of four perk cards plus a stamp, a reroll, or a banish — and the two cards that decide whether you survive long are infinite durability and double damage. Everything else about going far flows from managing those level-ups, your preparation at the church, and the stage-20 rollover. Note that the perk/card system comes from Endless runs specifically; the details below are based on a first-hand player video and a detailed Steam discussion from players, not official documentation.

How the perk card system works

Every time you level up during an Endless run, the game pauses and presents options. Per a player video that documented the system in depth, each level-up offers four cards plus, additionally, a stamp, a roll (reroll), or a banishment of any of the cards. Cards cover just about anything that exists in the game — items, vendors, and stations included. They fall into five broad groups:

• Permanent buffs that last the whole run (max health +25, +10% XP, movement speed, thorns, ammo spawn increase, shard pickup range).
• Stage-only buffs, some nearly mandatory, such as infinite durability, infinite ammo, and double damage — all of which can only be picked once.
• Utilities such as spawning a specific vendor, healing, repairing, or exiting.
• General spawns of something useful (storage, gun racks, food, trinkets).
• Specific item spawns — the game naming a random item for you, which players generally banish.

A player who reached roughly stage 18 and wrote a long Steam discussion about the mode describes the level-up screen as intrusive: it can trigger mid-jump, cancel attacks, and a mis-click can banish an important upgrade with no confirmation step. Expect the choice to appear at bad moments and be deliberate with your input.

Which cards to prioritize

One player with a personal best of 42 stages and five waves ranked around 23 of the cards. Their ordering, summarized for your decision-making:

The player also flags honorable mentions: tough companions (summoned allies such as a Novanian Guard or Desert snipers) are far from bad, and charm effects behave unusually well in Endless. On that note, players report that dark lamps and dog whistles do not work in Endless Mode — likely a bug, since the developer has not documented it as intentional. The same player saw only left-side gun racks spawn across 42 stages despite owning both, so consider consolidating your stored guns onto one side and testing which side spawns for you.

Level pacing: the strategy that makes long runs possible

Every level requires more XP than the last, so later in a run you earn fewer and fewer levels per stage while enemies grow bulkier and spawn more frequently. If you level too fast early, you will burn your best stage-only card opportunities on weak choices and hit late stages with nothing left. The counterintuitive core strategy from the player who hit stage 42: space out your level-ups and avoid picking XP that you do not need.

• XP left on the ground is pulled in at the end of a stage, but you do not level up there — you level up once, when you reach the next area, regardless of how much XP was left. So banking XP does not stack levels; it only raises the cost of your next one.
• Avoid permanent shard pickup range so you cannot accidentally vacuum XP.
• Save rerolls and banishes for the must-pick stage-only cards rather than spending them early.
• When you have the best perks in hand, you can deliberately dodge XP and camp rather than triggering another level-up with poor options.

1. Fill every church container before you start

   Load your church storage with one to two extra guns, repair kits, a large stack of health potions (players report the Forest grind is the easy source), food, and anything else you might need. Storage summons in-run are your restock line; without them, one player doubts they would have passed stage 10.

2. Bring defibs — four or five of them

   Defibs revive you and grant half of your current max health, so with 1000 HP that is 500 free health back. They can also spawn as cards mid-run. The catch: there is no clear notification when one triggers, so check your inventory after hard hits.

3. Build around infinite ammo and infinite durability

   Carry a couple of infinite-ammo guns at all times, but do not run only infinite-ammo guns — the infinite ammo card is better spent when you have variety. Parallel mag pairs well on infinite-ammo guns since reload speed stops mattering. Energy weapons ignore recoil penalties, making recoil-heavy oils free damage there.

4. Play stages 1–19 conservatively

   Skip XP-heavy picks, take melee cards only in the earliest stages, and hoard rerolls, banishes, and consumables for the later ramp.

5. Brace for the stage 20 rollover

   Every 20 stages, enemies grow in size and gain health and damage. Without the double damage card, rounds become a slog of attrition. This is the checkpoint where most runs die — go in with double damage, full storage access, and spare guns.

Gear notes for late stages

Player-tested builds emphasize a few oils: Tandem (+1 projectile, -15% damage) and Late Boom (+30 flat damage, -30% bullet speed) are top-tier on most guns; Gemini and Slow Punch are strong flat-rate alternatives. On the Arbiter, multi-chamber is effectively free because the gun fires all barrels at once anyway. The Neuraxis transforms with the infinite durability card — the longer it fires, the more accurate and fast it becomes, and with a Least Resistance enchantment it homes in on targets. A charm-scroll gun that converts enemies to your side is a favorite fail-safe, and charmed kills still drop full XP for you.

FAQ

Why is ammo not dropping in endless mode?

Ammo supply in Endless leans on cards and prep, not ground drops. The ammo-spawn card increases how much ammo you get from card pulls — one player who tested it found it does not noticeably increase ammo picked up off the ground, though each ammo card pull already gives around 500 rounds of any type. If you are running dry, it is usually because you level too slowly to pull ammo cards or entered under-stocked; load ammo into church storage and bring infinite-ammo guns.

Does double damage last the whole run?

No. Double damage is a stage-only card that can be picked only once per pick window, unlike permanent buffs such as max health +25. Re-securing damage output after each rollover is part of the challenge.

Do I need to beat the game before Endless Mode?

Players report that Endless assumes you have already beaten areas like Forest — "if you're playing Endless, you've already beaten Forest," as one video puts it — so treat main-game progression as the practical prerequisite. The exact unlock condition is not documented in official material.

What is the highest stage anyone has reached?

There is no official leaderboard. The player whose card rankings this page draws from cites a personal best of 42 stages and five waves, and notes that stages past 40 remain a slog even with double damage.

Next steps

• Build your gun pool with our SULFUR item attributes page — oil and enchantment interactions decide whether your infinite-ammo guns carry stage 30 and beyond.
• If you are still working through the campaign to unlock Endless, the SULFUR walkthrough covers the route through the main areas.
• New to the game's core loop? Start with the SULFUR beginner guide before optimizing card picks.

Check note (2026-11-06): Card mechanics and run strategies are drawn from first-hand player accounts — the "How Perks Work in SULFUR's Endless Mode" and "10 Guns That Make Endless Mode Easy in SULFUR" YouTube videos and a long Steam discussion on the mode. General release, platform, and 1.0 facts come from the official SULFUR Steam page. The exact Endless Mode unlock requirement and any official card list remain unconfirmed by Perfect Random.