#DHSeaDev — Card Battler — Chrome MV3 — Browser Game
Prismwar
Prismwar is a free, original six-color trading card game you play against a computer rival. Five colors you will recognise, and a sixth, the Undertow, that takes your opponent’s units for good. Build a deck from 250 cards, earn packs from quests, and unlock ten Ascendants with signed codes. No account, no purchases, no tracking.
ON THE CHROME WEB STORE BROWSER VERSION LIVE
Play Prismwar free at the DHSeaDev Arcade, with no install and no account. The Chrome extension, which opens the game in its own tab, is live on the Chrome Web Store as Prismwar — Six-Color Card Battler. That build is at 0.6.0: one-click deck building, a colour letter on every card so colour is never the only cue, and a plain-language First Steps guide after the tutorial — see what changed in 0.6.0 below. The browser version at the Arcade is the earlier 0.3.1 alpha and stays as it is. The Prismwar Ledger page explains codes and Ascendants.
Six colors
Go wide. Rally, Guard, Bulwark. Small bodies that hold a line together.
Fliers, Foresee, bounce. Out-draw the rival and slip past blockers with Drift.
Trade everything. Wither, Toll, Reclaim. Every death pays you back.
Swift attackers and burn to the face. Win before turn eight or not at all.
Bloom into extra Wellsprings and Grow the biggest bodies in the set.
The sixth color. Glimpse their hand, Ensnare their units, and keep what you take.
What changed in 0.6.0
Version 0.6.0 is about the first twenty minutes. Everything below came out of watching where a new player stalls.
Colour is never the only cue
Every card now carries its colour letter (W, U, B, R, G, P) and a coloured edge stripe, so the six colours stay separable without relying on hue alone.
Quick build
Press a colour and the game assembles a legal forty-card deck from the cards you actually own — cheap spells first, a capped top end, and the Wellsprings split evenly. It refuses rather than hand you a mana pile.
Deck advice in plain words
The editor tells you when your colour pips have no Wellspring that can pay them, when the curve is too heavy, or when there are too few units. None of it blocks Save.
First Steps
A short guide after the tutorial that names the four things to do next, instead of dropping you into an empty collection.
Why a duplicate turned to shards
The pack screen now explains the fourth-copy rule at the moment it happens, rather than leaving you to work out where the card went.
Coming from another card game
A section in the rules that maps Prismwar’s terms onto the ones you already know, and flags the three places it deliberately differs.
What the Rival was thinking
The match summary lists the turns that decided the game and why the computer player made the choice it did.
An edited save says so
A profile changed outside the game is marked, and the mark stays marked — it no longer clears itself on the next save.
Older releases are listed in the change history. This is the build you get from the Chrome Web Store; the earlier 0.3.1 alpha is still free to play at the DHSeaDev Arcade.
The game
250 cards
The Refraction set: 240 collectible cards across six colors, plus ten Ascendants — loyalty-driven legends a cut above the rest, one per deck.
Eight starters
Six single-color and two two-color decks built from commons: Order Vanguard, Current Tempo, Ledger Attrition, Spark Rush, Root Ramp, Undertow Thieves, Dawnfire Rush and Tidegrove.
A rival that thinks
The computer player scores every legal play, trade, block and ambush one move ahead and picks the best. Easy and normal difficulty, and a guided tutorial for the first match.
Fair packs
Five-card packs: slot four is always Uncommon or better, slot five always Rare or better, a Signature at most twelve packs apart, and the odds printed in the game.
Earn, never buy
Three daily quests, fifteen achievements, a pack for the first win of the day, dust for every match and every three-win streak, and crafting for anything you still lack.
Codes, not custom cards
Ascendants never appear in packs. They unlock only with codes DHSeaDev issues, each signed with ECDSA P-256 so the game can tell a real code from a forged one without asking a server.
Sound and motion
Three synth soundtracks — ambient, chiptune, synthwave — generated live with the Web Audio API, plus screen shake and cast effects. Sound, music, shake and motion each have a switch.
Yours to keep
Export a fingerprinted backup and import it anywhere. A save edited outside the game still loads, but its ledger card says so.
The Ledger
Every profile prints a ledger card: collection count, packs opened, record, achievements, Ascendants and deck list, fingerprinted by a Sig line. Post it as a stylized card on the shared Ledger Wall, download it as a picture, or paste the text anywhere. The wall is a playful shared list, not a leaderboard, and posting is always optional.
How it was built
Prismwar is written in plain JavaScript with no framework and no third-party game assets. The card art is procedural pixel art — a five-tone palette per color, light from the top left, and body shapes chosen from each card’s keywords — and a build gate hashes the geometry of all 250 cards so no two can share a picture. It is one of several DHSeaDev games with a computer opponent; VEILFALL does the same for solo hidden-role deduction, and Prism Cascade is the physics arcade game that shares its prism palette.
Questions
What is Prismwar?
Prismwar is a free, original six-color trading card game you play against a computer rival. It has a 250-card set, eight starter decks, packs earned from quests, and ten Ascendants that unlock only with codes. It needs no account and makes no network requests of its own.
Is Prismwar free?
Yes, and there is nothing to buy: packs come from playing. The Chrome extension is free on the Chrome Web Store, and the browser version is free at the DHSeaDev Arcade. Neither needs an account.
Which version am I playing?
Two builds exist. The Chrome extension is at 0.6.0, is the one that gets new work, and is live on the Chrome Web Store. The browser version at the DHSeaDev Arcade is the earlier 0.3.1 alpha, playable now with no install. Saves are not shared between them.
Is it a Magic clone?
No. Prismwar is an original design that borrows the shape of a color-pie card game and then adds a sixth color, the Undertow, whose whole identity is taking things and keeping them. Every card, name and piece of art is original and generated for this game.
Can I make my own cards?
No. Custom cards were removed so that the collection means the same thing for everyone. New cards arrive as expansions and as owner-issued codes posted on the Prismwar Ledger page.
Does it collect anything?
No. The game makes no network requests of its own, and the extension’s content security policy blocks them outright. Posting to the Ledger Wall is optional: a deliberate click that publishes the text of your ledger card to a public, third-party shared list. The full privacy policy is on this page.
Where is my collection saved?
On your device only: in Chrome’s local extension storage for the extension, or in the browser’s local storage for the browser version. Export a backup file from Settings to keep it or move it.
Sources and further reading
Written about Prismwar
- Prismwar: a six-color card game with a built-in AI opponent that runs entirely in the browserCoderLegion, September 11, 2026 — the feature list and tech stack.
- Three of my test gates had never heard of the game I was shippingDEV Community, September 11, 2026 — how seating Prismwar in the arcade exposed gates with hardcoded entry lists.
How it works
- SubtleCrypto: verify()MDN — the Web Crypto call behind code checking; ECDSA is a supported algorithm.
- Web Audio APIMDN — every sound and all three soundtracks are synthesized with it; the game ships no audio files.
- chrome.storageChrome for Developers — where the extension keeps your profile; data is cleared when the extension is removed.
- Manifest: content_security_policyChrome for Developers — the policy that lets the extension declare connect-src none.
- URI fragmentMDN — why a ledger card carried after # in a link is not sent to the server.
- Pixel Art Tutorial: BasicsDerek Yu — the principles the procedural card-art pass follows: limited palettes, a single light source, clean outlines.
- playhtmlThe open-source shared-state library behind the Ledger Wall.
- Prismwar LedgerCodes, Ascendants and the wall.
- Every DHSeaDev game, and where to play itThe games hub.
- The DHSeaDev ArcadeFree browser games, no install.
- All projectsExtensions, games and tools.
- VEILFALLSolo hidden-role deduction against the same kind of computer opponent.
- Prism CascadeThe physics arcade game that shares the prism palette.
- What changed in 0.6.0This page — the current release, in plain words.
Privacy Policy
Effective September 11, 2026 · applies to the Prismwar Chrome extension (version 0.3.0 and later), the browser version at the DHSeaDev Arcade, and the Prismwar Ledger Wall.
The short version
Prismwar has no accounts, no analytics, no advertising and no tracking, and DHSeaDev does not receive, sell or share any data about you. Everything the game knows lives on your device. The only thing that can ever leave it is text you deliberately copy, export or post.
What the game stores, and where
Your profile: the player name you type, your collection, decks, settings, quest and achievement progress, match record, and the codes you have redeemed. The Chrome extension keeps it in Chrome’s local extension storage; the browser version keeps it in that browser’s local storage for play.dhseadev.online. It stays on your device, is never transmitted, and is deleted when you uninstall the extension or clear the site’s data.
Permissions and network access
The extension requests one permission, storage. Its content security policy sets connect-src 'none', so Chrome itself blocks the extension’s pages from making network requests of any kind. Its background worker does one job: open the game in a tab, or bring that tab forward if it is already open. It does not read your browsing history or the content of other tabs.
Redeem codes
A code is checked on your device against a public key built into the game (an ECDSA P-256 signature). The code is not sent anywhere to be checked.
Things you choose to share
Copying a backup, a deck code or your ledger card puts that text on your clipboard only when you click the button. Exporting a backup saves a file to your device; importing reads the file you pick, locally.
The Ledger Wall (optional)
The ledger card is a short text summary: the player name you chose, the date, your collection count, packs opened, dust, match record, achievement and Ascendant counts, your deck names and colors, and a Sig line. The button “Post to the Ledger wall” opens the wall page with that text after the # in the link; browsers do not send that part of a link to the server. Nothing is published until you press “Post to the wall” on the wall page.
A posted card is public. The wall is built with playhtml, an open-source library, and its maintainer states that playhtml data is stored by a PartyKit instance under their account, unencrypted, and readable by anyone with the room name. DHSeaDev does not operate that service. Use a nickname you are happy to see in public, and email the address below to request that a post be removed.
Hosting
The browser version and the wall are static files served by Cloudflare Pages; as with any web host, Cloudflare processes connection data such as IP address and browser type to deliver them, under the Cloudflare Privacy Policy. The arcade’s home page shows anonymous play counts and star ratings, also through playhtml. This website, dhseadev.online, is hosted on WordPress.com and covered by the Automattic Privacy Policy.
Children
Prismwar collects no personal information from anyone, including children. The Ledger Wall is public, so younger players should not post a real name.
Changes
If this policy changes, the new version is published here with a new effective date, and the change is noted in the change history below.
Contact
Questions or removal requests: dhseadev@gmail.com
Change history
Chrome Web Store release — September 15, 2026. The 0.6.0 extension build is live on the Chrome Web Store as Prismwar — Six-Color Card Battler. The entries below are kept as they were written, so the two marked in preparation describe the state at that release, not today. The browser version at the Arcade remains the earlier 0.3.1 alpha.
0.6.0 — September 2026 (extension build, in preparation). A colour letter and a coloured edge stripe on every card, so colour is never the only cue. Quick build assembles a legal forty-card deck from what you own, and refuses instead of padding a thin pool out to forty Wellsprings. Plain-language deck advice for unpayable colour pips, a heavy curve and too few units — none of it blocking. A First Steps guide after the tutorial. The pack screen explains why a fourth copy becomes shards. A “coming from another card game” section in the rules. The Rival’s key moments in the match summary. The edited-save mark is now sticky and carries a written explanation. Dialogs trap and restore focus. Not on the Chrome Web Store yet; the browser version at the Arcade is unchanged by this release.
0.5.0 — September 2026 (extension build, in preparation). Replays: a finished match encodes to a code of about five hundred characters carrying the seed, both deck lists, every action, a checksum and the difficulty, and a read-only viewer walks it back step by step with a board at every turn. A name is asked for on the first-run screen instead of assigned. Settings, challenge and quest spacing rebuilt from measured gaps rather than by eye. Not on the Chrome Web Store yet; the browser version at the Arcade is unchanged by this release.
0.4.2 — September 2026 (extension build). Pairing lines drawn between attackers and blockers, packs revealed one card at a time behind a re-entrancy guard, keyboard shortcuts gated on Ctrl/Cmd/Alt, the card back hidden from assistive technology, the live region moved outside the re-rendered view, and the footer version read from the engine instead of a hard-coded string.
0.3.1 — September 2026. The browser version is live at the DHSeaDev Arcade. Ledger Wall fixes: a full wall keeps accepting new cards, the Post button waits until the wall has connected, and cards with long deck lists fit. Player names are trimmed without breaking an emoji.
0.3.0 — September 2026. Eight commons-only starter decks; uniform cards with flip-to-read, flavor text and an enlarged view; collection grouped by rarity; pixel-art pass across all 250 cards; three synth soundtracks, screen shake and cast effects; daily first-win pack and streak dust; slot-four Uncommon guarantee; the Ledger Wall. Privacy policy published September 11, 2026.
0.2.0 — September 2026. 250-card set, ten Ascendants unlocked by signed codes, custom cards removed, profile integrity fingerprint, tutorial and smoothed opening hands.
0.1.0 — September 2026. First playable: engine, computer rival, deck builder, packs, quests, achievements.
NEXT: THE BUILD — A round trip cannot test its own driver, on the replay format and the defect forty-five green assertions could not see.
More from DHSeaDev: MTG Cart Companion if you play physical trading card games, or the full projects page for everything else.