Ratatan Episode Progression: Upgrade Costs, Oaths & Dock Path

Mapping out a clean run through Ratatan's four episodes comes down to understanding three intertwined systems: the Support Desk that gates your run-by-run economy, the Ratatan Dock that converts that economy into permanent power, and the Oath / Melodium track that turns one-shots into new content. This guide walks the full Ratatan episode progression path step by step, with the upgrade cost tables, threshold numbers, and decision points the community has stress-tested across early access builds.

Support Desk Upgrades and Per-Episode Cost Curves

The Support Desk is the only vendor visible between runs and the most consistent spending sink in the early game. Every desk upgrade raises the baseline reward you earn from completing an episode, which means the cost you pay at the desk compounds back into your next attempt. Players who skip the desk in Episode 1 routinely find themselves stuck on Episode 2 boss HP gates, because their reward ceiling is still pegged to the starter bracket.

How the Support Desk Economy Works

Each episode hands out a fixed reward pool on first clear and a smaller consolation reward on repeat clears. The Support Desk converts raw reward currency into permanent multipliers on that pool. There are five desks, and each one lifts the multiplier by a set percentage. According to the official Ratatan Standard and Deluxe package store page, the desk system is the intended loop for players who want steady, predictable growth without grinding optional encounters.

The cost curve is not linear. Each step roughly doubles the previous, which is why dumping everything into Desk 4 before touching anything else is a common beginner trap. The expected reward from a single Episode 1 clear is not enough to clear a Desk 3→4 jump, so you will sit at the desk screen with insufficient funds for two or three runs.

Recommended Spending Order

Veteran players in community testing tend to follow a three-phase desk plan because Ratatan's Support Desk multiplier compounds aggressively — a 2.0x output at Desk 2 roughly doubles your per-run Ratatta spawn rate, which in turn accelerates Melodium farming and the unlock of late-game Oaths tied to Episode 4.

• Phase 1 (Episodes 1–2): Buy Desk 1→2 immediately, then Desk 2→3 as soon as you can. Both pay for themselves inside two episode clears.

• Phase 2 (Episodes 2–3): Hold back from Desk 3→4 until you have 1,800 currency in the bank. The 200 buffer covers the consolation reward variance from a failed Episode 3 attempt.

• Phase 3 (Episodes 3–4): Desk 4→5 is the largest single jump. Do not attempt it without at least one full Episode 4 clear logged, because the cost is designed around players who have already unlocked the Episode 4 reward bracket.

The Support Desk upgrades are a safer investment than the per-episode shop because they are never lost on death. Per-episode weapons bought from the in-run vendor reset every attempt, but the desk multiplier carries forward indefinitely, including into the Episode 4 true ending route.

The Ratatan Dock: From Reward Currency to Permanent Power

While the Support Desk handles reward multipliers, the Ratatan Dock is where you actually convert accumulated currency into permanent stat gains and unlock the late-game vendor NPCs. The dock sits at the hub between episodes and is the visual centerpiece of the meta-progression screen. The two systems are deliberately separated so that players who only run one episode still see meaningful growth.

Dock Stations and Their Costs

The dock has six stations. Three of them are combat upgrades, two are utility, and one unlocks a new vendor. Each station has a five-tier upgrade ladder, and tiers do not need to be bought in order. You can jump straight to tier 3 if you have the currency, although community data suggests linear progression is roughly 8–12% more efficient per reward spent.

The Ratatan Dock stations are where the long tail of progression lives. Attack Rig and Vital Pad are obvious first picks for anyone struggling with Episode 2 boss damage, but Tempo Core tends to outperform both in Episode 3, where the beat-window timing window tightens and most deaths come from missed cue beats rather than raw HP loss. Memory Rune is a hidden gem: the reroll token it grants is what lets experienced players push Episode 4 consistently, because one bad shop roll is usually the difference between a clean clear and a reset.

Why the Dock Path Matters for Episode 4

Every Episode 4 ending branches based on which dock stations you have upgraded before entering the episode for the final time. The minimum threshold for the true ending route is four stations at tier 3 or higher, plus a fully cleared Vendor Bay. Players who hit Episode 4 with only Attack Rig and Vital Pad maxed will see the Episode 4A ending and be locked out of the post-credits content. This is by design, and the developers confirmed in the official Ratatan Development Log #10 that the dock system was specifically tuned so that the Episode 4 true ending requires multi-station investment.

For a deeper breakdown of the broader Ratatan progression loop, the Ratatan progression guide covers the goddess games and lottery system that sit alongside the dock. Those systems feed directly into Episode 4 preparation, because Goddess Game rewards and melodium won through the lottery both accelerate dock station upgrades, letting players hit the four-tier-3 threshold without grinding Support Desk side missions for raw upgrade costs.

Oaths: Episode-Gated Permanent Buffs

Oaths are the most misunderstood layer of Ratatan's progression because they look like a per-run choice but actually function as permanent account-wide buffs once accepted. When you clear an episode, the Oath screen offers one of three randomly drawn oaths, and accepting any one of them locks the buff in for every future run on that save file.

Oath Categories and Episode Drop Rates

The 24 oaths are split evenly into four six-oath categories — Combat, Tempo, Fortune, and Covenant — with each episode favoring a weighted draw from its assigned pool rather than a flat distribution. Episode 1 pulls exclusively from Combat, Episode 2 blends Combat and Tempo, Episode 3 adds Fortune into the rotation, and Episode 4 unlocks the locked-out Covenant pool alongside continued Fortune odds. Roughly 70% of any given run's oath drops come from the episode-specific pool, while the remaining 30% rolls against the universal 24-oath table, which is why a Tempo-locked build can still surface a Fortune payout mid-run. This weighted system is what makes ratatan episode progression feel layered: skipping an episode means forfeiting the oaths tied to its pool entirely, since cross-episode carryover does not refresh missed drops.

The Covenant category is the Episode 4 gate. You cannot pull a Covenant oath before clearing Episode 4 once, and the six Covenant oaths are the only buffs that count toward the true ending checklist. Players who clear Episode 4 three times without taking a Covenant oath will eventually see the prompt forced at the start of run four.

Stacking Rules and Trade-offs

Oaths do not stack infinitely. Each category has a soft cap of three active oaths, and beyond three the diminishing returns kick in hard. Community testing reports that a fourth Combat oath adds only 12% of the bonus a third one provides, so the optimal pattern is three oaths across three different categories, not four oaths in one. The ratatan oaths system is tuned around that three-category sweet spot, and the developers confirmed in early patch notes that the diminishing-returns curve is intentional to keep late-game variety high.

Melodium: The Late-Game Currency and Crafting Layer

Melodium enters the picture at Episode 3, and by Episode 4 it is the only currency that matters for top-tier upgrades. It drops from a small set of high-value encounters: Episode 3 mid-bosses, the Episode 3 gauntlet, and the Episode 4 pre-finale vendor. Melodium does not drop from trash mobs, which is the single biggest reason players feel "stuck" between Episode 3 and Episode 4 — they are farming the wrong encounters.

Melodium Sources and Drop Rates

A single maxed Melodium recipe costs 240 units, which means the realistic farming window is two clean Episode 3 clears plus the Episode 4 vendor visit, all before the true ending run. The ratatan goddess altar deep dive covers how the goddess lottery interacts with Melodium rolls for players who want to squeeze extra value from every Episode 3 clear.

What Melodium Actually Buys

Melodium recipes are the only upgrades that modify your character mid-run rather than between runs. There are nine recipes in the current build, and each one is a one-time unlock per save file. The two highest-impact recipes are Iron Lattice (reduces all incoming damage by 15% for the entire run) and Copper Echo (duplicates every reward drop, which roughly doubles the desk and dock currency you earn from a single run). Most players save their first 240-unit spend for one of these two, then bank the rest until the Episode 4 finale.

Building the Optimal Episode 4 Path

Stacking the Support Desk upgrades, Melodium economy, Dock stations, and Oath buffs into a single episode route looks like four spreadsheets taped together, but experienced players treat the four layers as one cascading investment rather than independent grinds — a Desk 3 Support Desk line that costs 1,200 reward currency is what unlocks the Lucky Cove slot in the first place, and that slot is what generates the reroll tokens required to hit the Episode 4 true ending oaths. The order below is the practical route that follows from that dependency chain.

1. Episodes 1–2: Max the Support Desk to level 3, take three Combat or Tempo oaths, and clear Episode 2 with a comfortable HP buffer.

2. Episode 3 first clear: Bank at least 1,800 reward currency, take your first Fortune oath, and start Melodium farming from the mid-bosses.

3. Episode 3 second clear: Push to Desk 4 and start upgrading the Ratatan Dock's Lucky Cove and Memory Rune stations.

4. Episode 4 first clear: Unlock the Vendor Bay, take a Covenant oath if offered, and spend Melodium on Iron Lattice or Copper Echo.

5. Episode 4 true ending run: Enter with four dock stations at tier 3+, at least one Covenant oath active, and a stocked reroll token from Memory Rune.

Players who want to optimize their per-run command economy should also look at the ratatan melee characters breakdown, because Cobun formation choices shift the reward rolls by enough to change which Support Desk upgrade you can afford next.

The four-layer system looks heavy on paper, but each layer feeds the next in a way that keeps any single run from feeling wasted. A failed Episode 3 attempt still pays out the consolation reward, which feeds the Support Desk, which feeds the Dock, which feeds the next Episode 3 attempt. That loop is the entire point of the ratatan episode progression design, and once it clicks, the Episode 4 true ending clears itself over two or three focused sessions.

Frequently Asked Questions

How long does a full ratatan episode progression run take?

A clean four-episode run takes roughly 45–60 minutes on a first-time save, including hub time. Experienced players with maxed Support Desk and Dock stations can clear all four episodes in 25–30 minutes, which is the typical speedrun benchmark for the current build.

Can I reset my oath choices if I pick badly?

No, oaths are permanent per save file. The only soft reset is starting a new save, which keeps none of the dock or desk progress. Community testing strongly suggests always taking a Fortune or Covenant oath over a Combat oath in Episode 3, because the late-game value is much higher.

What is the cheapest way to hit the Episode 4 true ending requirements?

The minimum cost path is Desk 3, four dock stations at tier 3, and one Covenant oath. That setup requires roughly 6,000 reward currency total, which lands after about 8–10 clean episode clears. Skipping any one of those three pillars locks you out of the true ending cutscene.

Is Melodium shared across all characters?

Yes, Melodium is account-wide and persists across every character you build. The only thing that does not carry over is the per-run shop inventory and the in-run weapon rolls, both of which reset every attempt. This is why banking Melodium for a single big recipe is more efficient than spending it on small per-run upgrades.