To unlock all hidden achievements in Zenless Zone Zero and claim hundreds of unlisted Polychromes, Proxy players must complete specific unmentioned interaction triggers across New Eridu, execute precise tactical combat mechanics in Hollow Zero, max out Agent Trust dialogues, and manipulate daily street cycles on Sixth Street and Lumina Square. Unlike standard Inter-Knot milestones that naturally register through story progression, hidden achievements require deliberate actions—such as petting Howl at the newsstand across specific daily cycles, intentionally failing arcade minigames under exact parameters, or stacking maximum Corruption tiers during high-level Hollow runs.
Street Life and City Exploration Hidden Achievements
Exploring New Eridu’s street hubs reveals dozens of secret trophies that never show up in your standard Inter-Knot checklist until triggered. Managing your daily time slots—Morning, Afternoon, Evening, and Midnight—is fundamental to catching local NPCs and interactive objects in their hidden states. Much like managing urban systems in titles like Cities Skylines 2, keeping track of daily routines across New Eridu rewards meticulous planning.
Howl’s Newsstand and Daily Scratch Cards
At Howl’s Newsstand on Sixth Street, interacting with the daily Scratch Card holds multiple hidden achievements:
- Lucky Dog: Win the top grand prize (3 Polychromes) from Howl’s scratch card three separate times.
- Better Luck Next Time: Draw the lowest consolation prize (1000 Dennies) five days in a row without winning a Polychrome tier.
- Good Boy Howl: Intercept Howl by selecting the "Pet Head" dialogue option on 10 consecutive real-world days before taking your scratch card.
Coff Cafe Secrets and Late-Night Encounters
Tin Master’s Coff Cafe on Sixth Street is more than just an energy restoration point for Battery Charge. Ordering specific regional brews during targeted hours unlocks secret entries:
- Espresso Specialist: Drink every unique coffee variant available on the menu at least once, including rotation-exclusive brews during special events.
- Midnight Caffeine: Visit Coff Cafe at exactly 02:00 (Midnight cycle in-game) and talk to the weary Proxy sitting on the curb next to the shop.
- Vending Machine Technician: Interact with the vending machine beside Random Play 10 times consecutively until the machine shakes and drops a free Denny.
Hollow Zero and Combat Secret Achievements
Hollow Zero serves as New Eridu’s primary roguelike endgame challenge, holding some of the most technical secret achievements in HoYoverse history. To claim these combat trophies, players must manipulate gear, Resonium card stacks, and specific squad compositions, similar to tailoring builds in games featured on our Solo Leveling Arise tier list.
Resonium Stacking and Corruption Manipulation
In Hollow Zero runs (Withering Garden or Rayed Garden), targeting absolute maximum stat thresholds yields hidden titles:
- Absolute Fortress: Collect 8 Shield-type Resoniums in a single exploration run without allowing your squad shield to break once.
- Living on the Edge: Reach maximum Corruption Level 5 (500 Corruption) and complete the final floor boss fight against Nineveh without losing a single Agent.
- Resonium Collector: Obtain 25 or more Resonium items in a single Hollow Zero run by utilizing gear resets at rest stations.
Boss Mechanics and Perfect Assist Counters
Mastering enemy telegraphs is required for boss-specific hidden achievements against elite foes like Dullahan, the Marionette Twins, and Nineveh:
- Perfect Rhythm: Execute 10 consecutive Perfect Assists (Parry Assists or Evasive Assists) in a single encounter against Dullahan without getting hit.
- Tentacle Dodge Master: Dodge 5 consecutive whip attacks from Nineveh’s tentacle appendages within a 15-second window.
- Faction Synergy Blast: Trigger 5 Chain Attacks in a single encounter utilizing a complete faction-matched squad (e.g., Victoria Housekeeping with Ellen Joe, Von Lycaon, and Corin, or Cunning Hares with Anby, Nicole, and Billy). For players familiar with squad synergy mechanics in Epic Seven team compositions, lining up character affinities is essential for maximizing burst windows.
Agent Trust and Coff Cafe Hidden Interactions
Building affinity with your unlocked Agents through the Inter-Knot Messenger system unlocks deep character lore along with unlisted Polychrome payouts. Reaching Trust Rank 4 (Trust Trust) with any Agent opens up secret hangout events around Lumina Square, Bellevue, and Brant Street Construction Site.
Secret Dialogue Triggers and Hangouts
When hanging out with Agents, specific choices yield hidden achievements rather than standard Trust points:
- Movie Buff: Take three different Agents (such as Nicole, Anby, and Soldier 11) to watch films at the Random Play video store and select their favorite genre every time.
- Brant Street Tour: Trigger a joint encounter by bringing both Ben Bigger and Anton Ivanov to the construction site area during the Evening cycle.
- Quiet Observer: Decline an Agent’s hangout request twice over DM, then catch them standing outside Random Play in person to unlock a special apology dialogue.
For more details on HoYoverse character design and combat logic, check out our guide on Honkai Star Rail offensive strategies, which shares tactical similarities with ZZZ's squad dynamics.
Arcade Minigames and Newsstand Trophies
Located on Sixth Street, the Godfinger Arcade contains two main retro minigames: Snake Duel and Soul Hounds III. Both games contain dedicated hidden achievements that require sharp reflexes and non-standard playstyles.
Snake Duel Trophies
To claim all hidden trophies in Snake Duel, jump into solo or 4-player competitive modes:
- Pacifist Snake: Survive for 2 full minutes in Snake Duel single-player mode without eating a single bean or growing your body length.
- Giant Anaconda: Reach a total body length of 100 segments in a single match.
- Double Knockout: Eliminate an opponent snake while simultaneously crashing into their tail in multiplayer mode.
Soul Hounds III Trophies
Soul Hounds III tests your vertical drilling speed through collapsing block layers:
- Deep Diver: Reach a depth of 500 meters without suffering spike damage or suffocating due to low oxygen.
- Greedy Miner: Collect 50 gems in a single run without using extra drilling boosts.
- Instant Regret: Fall into a spike trap within the first 5 seconds of starting a floor.
If you enjoy tackling bite-sized arcade challenges while playing on portable devices, take a look at our roundup of the best co-op games verified for Steam Deck to find top-performing handheld titles.
Officer Mewmew Medals and Location-Based Secrets
Officer Mewmew, the mascot standing guard near the convenience store on Sixth Street and in Lumina Square, manages the town’s civic medal program. While standard medals list their goals outright, several hidden achievements are tied directly to fixing New Eridu’s infrastructure.
Repairing Lost Bangboo
Scattered throughout Sixth Street, Lumina Square, and the Ballet Twins Road are broken Bangboo units needing technical assistance:
- Eridu Technician: Repair 10 broken Bangboo across New Eridu maps by solving their circuit wiring puzzles.
- Cargo Assist: Find and assist all 5 lost Freight Bangboo carrying heavy crates in Lumina Square during rainy evening cycles.
HIA Commemorative Coin Collections
HIA Commemorative Coins are awarded by talking to specific residents marked by faint yellow prompts during specific times of day. Unlocking all coin achievements requires key timing:
- Coin Collector I & II: Turn in 10 and 20 HIA Commemorative Coins to Sage in a Barrel on Sixth Street.
- Midnight Whisperer: Speak to the sleepy NPC standing outside the convenience store at exactly 00:00 midnight game time to obtain the final secret Sixth Street coin.
Consult the official Zenless Zone Zero website and track your stats via the HoYoLAB official battle chronicle to verify your active achievement completion percentage. Players on PC can also manage their client via the Epic Games Store page for continuous auto-updates.
Efficiency Tips for Farming Polychromes via Achievements
If your goal is to quickly accumulate Polychromes for upcoming Agent banners, optimizing your daily achievement hunting routine is critical. Follow these actionable steps to maximize your output per session:
- Use In-Game Time Fast-Forward: You can skip time forward once per in-game day using the clock interface on your bed or top-left menu bar. Use this feature to jump straight to Midnight or Evening cycles to claim time-gated HIA coins and trigger NPC conversations.
- Combine Hollow Zero Tasks: Never attempt Hollow Zero hidden achievements individually. Combine high Corruption runs with specific Resonium collection goals (such as stacking 8 Shield Resoniums) to clear multiple achievements in a single 20-minute run.
- Check Officer Mewmew Stamps Daily: Officer Mewmew's stamps directly hand out 5 to 10 Polychromes each. Complete location challenges in Sixth Street before moving to Lumina Square to unlock regional tier rewards.
- Keep track of Godfinger Daily Arcade Missions: Arcade hidden achievements overlap with daily Inter-Knot tasks, giving you extra EXP alongside direct Polychrome drops.
By systematically sweeping Sixth Street, pushing Hollow Zero runs to their tactical limits, and executing exact combat triggers, you can unlock every hidden achievement in Zenless Zone Zero and claim every single free Polychrome New Eridu has to offer.