Filthium Zero 100% Achievement Guide – How to Unlock

Looking to get 100% of the achievements in Filthium Zero? This guide explains the fastest ways to unlock every achievement, including the hidden Steam achievements.

There are 23 achievements in total. 18 are visible in-game, while 5 are hidden and can only be seen on Steam.

The good news is that many achievements can be completed naturally while working toward others. The key is understanding one extremely powerful mechanic early: Jumping and Slamming.

Filthium Zero 100% Achievement Guide – How to Unlock

Filthium Zero may be a twin-stick shooter, but shooting is not always the strongest way to survive.

Your most useful tool is the combination of Jumping and Slamming.

Dashing

You can dash in the direction you are moving.

However, dashing does not make you completely safe. You can still take damage while moving or when reaching your destination.

Jumping

You begin with one Jump charge.

Jumping lets you:

• Move safely through dangerous areas.
• Avoid enemies.
• Cross holes.
• Stay airborne.

Falling into holes does not instantly kill you, but it deals damage and forces you to jump back out.

Slimes

Slimes act like bouncing pads.

Touching a Slime launches you back into the air, allowing you to stay airborne and chain jumps together.

Slamming

This is where the game becomes much easier.

While airborne, press Dash to Slam into the ground.

After landing a Slam, you receive roughly one second of invulnerability.

This allows you to repeatedly:

1. Jump into the air.
2. Slam into the ground.
3. Use your brief invulnerability.
4. Jump again.

Once you build enough Air Jump charges, repeatedly Slamming becomes one of the safest ways to survive while dealing damage.

Learn this mechanic early. It is essential for several of the hardest achievements.

Best Perks to Prioritize

You will not always get the exact upgrades you want, so don’t expect a perfect build every run.

However, several perks should usually receive priority.

1. Experience Gain

Take Additional Experience whenever possible.

More experience means:

• More level-ups.
• More perks.
• More damage.
• More mobility.
• A stronger build overall.

Experience Gain is one of the best upgrades for almost every achievement run.

2. Air Boost

Air Boost is extremely important.

It has six levels, eventually providing a significant reduction to your recharge time.

When fully upgraded, you can have three Jump charges, each with its own cooldown.

With enough Air Boost, you can repeatedly Jump and Slam while staying relatively safe from enemy attacks.

For airborne and Slime-related achievements, this should be one of your highest priorities.

3. Damage

Take damage upgrades whenever they appear.

This includes:

• Overall Damage.
• Slam Damage.
• Weapon Damage.

Even if your build focuses on Slamming, additional damage makes bosses and enemy waves much easier.

4. Ultimate Charge

Ultimate Charge helps you recover your Ultimate ability faster.

Your first Ultimate can help clear large groups of enemies, but the second Ultimate is particularly important for difficult achievement runs.

With enough Ultimate Charge upgrades, you can use your Ultimate repeatedly as:

• An emergency escape.
• A way to retrieve your canister safely.
• A panic button when you’re out of Jump charges.
• A powerful damage tool.

5. Critical Chance and Critical Damage

Early in a run, prioritize Critical Chance.

After upgrading your Critical Chance through the shop, start prioritizing Critical Damage instead.

This gives you a better balance between landing critical hits and making those hits powerful.

Important Unlocks and Equipment

Some of the best items for achievement hunting are themselves locked behind achievements.

Because of this, your first few runs may feel slower.

Second and Third Optics

The second Optic unlocks after dealing approximately 15,000 total damage.

The third Optic requires spending 10 minutes in the air.

The third Optic is especially useful because it provides:

• Additional Health.
• Slam Damage.

The airborne requirement may take around two or three runs, depending on how heavily you focus on staying in the air.

Bare Fists

For many Slam-focused builds, weapons are less important than you might expect.

You cannot effectively use your weapons while airborne, making them less useful for a playstyle based around constant Jumping and Slamming.

Unlock Bare Fists, which allows you to run without a weapon.

The unlock requires approximately 500 Slime jumps.

Fortunately, you can work toward this while completing other Slime-related achievements.

Useful Item Choices

Two important item choices are:

Slime Amount

This is useful while completing Slime achievements.

It unlocks after Slamming approximately 450 Slimes.

Ultimate Charge

Once your Slime-related achievements are finished, Ultimate Charge becomes a much stronger choice.

It is particularly useful for difficult runs where your Ultimate is needed for survival.

Shop Upgrade Priorities

You do not necessarily need to fully upgrade the entire shop.

However, several upgrades make achievement hunting much faster.

Prioritize the following:

1. Filthium Gain
2. Extraction Speed
3. Damage
4. Critical upgrades
5. At least one level of Healing

Maxing Filthium Gain and Extraction Speed early will help you earn currency faster and progress through related achievements more efficiently.

Easy Achievements

Several achievements unlock naturally during your first few runs.

These include achievements related to:

• Starting your first run.
• Placing a barrel.
• Collecting your first Filthium.

Simply play normally, and these should unlock without requiring any special strategy.

Boss Achievements

First Boss

The first boss appears after approximately 4 minutes.

Use this encounter to practice your Slam strategy.

Don’t feel pressured to defeat everything with weapons. Staying mobile and repeatedly Slamming is often safer.

Second Boss

The second boss appears after approximately 10 minutes or after you collect all available Filthium pools.

This boss takes significantly more damage and can take some time to defeat.

By this point, you should ideally have:

• Strong Air Boost upgrades.
• Increased Slam Damage.
• Good overall Damage.
• A reliable Ultimate.

Getting comfortable with Slamming before reaching this boss makes the fight much easier.

Defeating the second boss also helps unlock progression-related achievements.

Difficulty and Score Attack Achievements

After completing a run on a difficulty level for the first time, you can progress to the next difficulty.

Move up whenever you’re comfortable.

The Score Attack achievement can also unlock at the end of a successful run.

Higher difficulties can actually make some progression requirements faster because you can collect Filthium more efficiently.

Filthium Collection Achievements

Some achievements require collecting large amounts of Filthium.

On normal difficulty, this usually takes around three to four full runs.

Focus on:

• Smashing crystals.
• Collecting Filthium pools.
• Improving Filthium Gain.
• Increasing Extraction Speed.

On higher difficulties, the required Filthium can be collected much faster, potentially taking only around two runs on the highest difficulty.

Damage, Combo, and Enemy Achievements

Several achievements can be completed naturally by focusing on enemies with Slam attacks.

Try to complete multiple objectives at once by:

• Slamming enemies.
• Building your damage.
• Maintaining combos.

If you’re struggling with damage or combos, melee weapons such as the following can help:

• Hammer.
• Arc Blade.

Perks such as Mines and Turrets can also be useful because they continue damaging enemies and help keep your combo alive.

Don’t obsess over maintaining your combo every second. A strong late-game build can naturally generate the damage and combos you need.

Airborne and Slime Achievements

These are some of the most time-consuming achievements in Filthium Zero.

Slimes do not always appear frequently, so you’ll need to actively focus on them during several runs.

Spending Time in the Air

Staying airborne for the required amount of time can take roughly two full runs of constant flying.

Prioritize:

• Air Boost.
• Air Mobility.
• Jump charges.
• Slime jumps.

Slime Achievements

Slime-related achievements may take approximately four to five runs if you focus heavily on them.

Whenever Slimes appear:

• Bounce from one to another.
• Use Jump charges to stay airborne.
• Slam when appropriate.
• Continue chaining movement.

You can work toward multiple Slime achievements during the same runs.

Chain 25 Slime Jumps

Chaining 25 Slime jumps is difficult but manageable with the right build.

Before attempting it, try to get:

• All six levels of Air Boost.
• Several Air Mobility upgrades.

Move carefully from one Slime to another.

If there are no Slimes nearby, use your Jump charges immediately after bouncing to maintain altitude and search for the next target.

Don’t Look Down

Another airborne achievement can be completed alongside Slime chains.

A useful strategy is:

1. Bounce from approximately three Slimes.
2. Quickly use all three Jump charges.
3. Continue gaining altitude.

This should provide enough height to unlock Don’t Look Down.

The Hardest Achievements

The final achievements require both preparation and skill.

Having the right equipment and upgrades makes a massive difference.

Bare Fists Runs

When using Bare Fists, Slamming becomes mandatory.

Since you cannot rely on weapons while airborne, your Slam damage is your main offensive option.

You also cannot safely Jump whenever your canister is left on the ground, so retrieving it can become dangerous.

Your second Ultimate is extremely useful here.

The Second Ultimate

Unlike the first Ultimate, the second Ultimate gives you:

• Invulnerability.
• Increased movement speed.
• Damage against nearby enemies.

The effect lasts approximately 8 seconds.

Use it when:

• You need to retrieve your canister.
• You are surrounded.
• You run out of Jump charges.
• You need an emergency escape.

With roughly eight Ultimate Charge upgrades, you may be able to recharge it quickly enough to use it repeatedly throughout difficult runs.

Fast Filthium Extraction Achievement

One of the harder objectives requires you to empty Filthium pools quickly.

The key is speed.

Recommended Setup

Take the Extraction Barrel perk whenever it appears.

This helps you safely retrieve the barrel after it finishes extracting.

Also upgrade the Extractor in the shop.

Keep an eye on the gauge in the bottom-left corner while collecting and depositing Filthium.

Best Strategy

1. Place your barrel.
2. Wait for excavation to finish.
3. Immediately retrieve the barrel.
4. Move quickly toward the deposit point.
5. Check the map to plan your route.
6. Collect nearby pools whenever possible.

Don’t waste time traveling across the map for a single pool if several nearby pools can be collected along the way.

Efficiency matters more than playing cautiously.

Boss Tips for Achievement Runs

Both bosses can become dangerous when you’re trying to complete specific objectives.

First Boss

The first boss can often be avoided while your barrel is busy.

If necessary, you can even use enemy damage strategically to launch yourself into the air toward your barrel.

If you cannot safely reach the barrel, use your Ultimate.

Second Boss

The second boss becomes particularly dangerous after collecting the final Filthium barrel.

Make sure you enter the final fight with:

• Enough Jump charges.
• A strong Slam build.
• A charged Ultimate if possible.

Don’t waste your Ultimate before the final moments if you know the second boss is approaching.