diff --git a/index.html b/index.html
index 326812b..c08b6cf 100644
--- a/index.html
+++ b/index.html
@@ -12,7 +12,10 @@
     
     <a href="/games/Cyst_Kid/index.html">Cyst Kid</a>
     <br><br>
-    <a href="/games/test/index.html">Kidney Lab</a>
+    <a href="/games/kidney_lab/index.html">Kidney Lab</a>
+    <br><br>
+
+    <a href="/games/sys_digger/index.html">Sys Digger</a>
     <br><br>
   </div>
 
diff --git a/sys_digger/CLAUDE.md b/sys_digger/CLAUDE.md
new file mode 100644
index 0000000..0aaca65
--- /dev/null
+++ b/sys_digger/CLAUDE.md
@@ -0,0 +1,59 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Running the game
+
+Open `index.html` directly in a browser — no build step, no server required.
+
+```bash
+open index.html
+```
+
+There are no tests, no linter, and no package manager.
+
+## Architecture
+
+Pure vanilla JS/HTML/CSS game. No frameworks, no modules — all files are loaded as classic `<script>` tags and share a single global scope. **Load order matters**:
+
+```
+constants.js  →  atom.js  →  render.js  →  game.js
+```
+
+### File responsibilities
+
+| File | Role |
+|---|---|
+| `constants.js` | Single source of truth for every tunable value (speeds, counts, radii, timing). Edit here first when tweaking gameplay feel. |
+| `atom.js` | `IncomingAtom` class — construction, per-frame movement, docking logic, self-draw. Reads globals from `game.js` (`canvas`, `CX`, `CY`, `anchorPoints`, `docks`, `gameOver`) and calls `burst()`, `updateCystinstein()`, `triggerGameOver()` from `render.js`/`game.js`. |
+| `render.js` | All canvas drawing: background, central molecule, anchor points, particles, click effects, and the Cystinstein side-panel. Also owns `burst()` (particle spawner) and `updateCystinstein()`. Reads `ctx`, `cysCtx`, `CX`, `CY`, `anchorPoints`, `particles`, `clickEffects`, `docks` from `game.js`. |
+| `game.js` | Game state, `requestAnimationFrame` loop, input handling, leaderboard (localStorage), screen transitions (intro → game → game-over → intro). Declares all shared mutable globals consumed by the other files. |
+| `index.html` | CSS + HTML structure only. Houses the intro screen, attract screen, game-over overlay, leaderboard table, and the kidney-shaped Cystinstein side panel (inline SVG border). |
+
+### Global state (declared in `game.js`, used everywhere)
+
+`canvas`, `ctx`, `cysCanvas`, `cysCtx`, `CX`, `CY`, `score`, `docks`, `gameOver`, `gameStarted`, `incomingAtoms`, `anchorPoints`, `particles`, `clickEffects`, `stars`.
+
+### Screen flow
+
+```
+Boot → Intro  ──(30 s idle)──→  Attract (highscore)
+              ←─(any key/click)─
+  │
+  └─(START clicked)──→  Game loop
+                            │
+                        (6 docks)──→  Game-over overlay
+                                          │
+                                      (Play Again)──→  Intro
+```
+
+### Leaderboard persistence
+
+Stored in `localStorage` under key `sysdigger_leaderboard` as a JSON array of `{name, score}` objects, capped at 10 entries, sorted descending by score.
+
+### Key design constraints
+
+- Anchor points activate (turn red) only when the incoming atom **enters the visible viewport**, not at spawn time — see `IncomingAtom.update()` in `atom.js`.
+- Difficulty ramps automatically: `spawnInterval` decreases by `SPAWN_DIFFICULTY_STEP` each spawn, floored at `SPAWN_INTERVAL_MIN`.
+- The custom cursor is a data-URL SVG pill embedded directly in CSS on the `canvas` selector.
+- The Cystinstein side panel uses an inline SVG with a bezier kidney path for its border; the interior atom-cluster is drawn on a separate `<canvas id="cystinstein-canvas">` by `updateCystinstein()` in `render.js`.
diff --git a/sys_digger/game.js b/sys_digger/game.js
index f3c6487..e2902ed 100644
--- a/sys_digger/game.js
+++ b/sys_digger/game.js
@@ -189,11 +189,67 @@ function restartGame() {
     document.getElementById('name-form').style.display = 'flex';
     document.getElementById('overlay').classList.remove('active');
     document.getElementById('intro').classList.remove('hidden');
+    startIdleTimer();
     initAnchors();
     updateCystinstein();
 }
 
+// ─── Attract mode ────────────────────────────────────────────────────────────
+const ATTRACT_DELAY = 30_000;
+let idleTimer = null;
+
+function startIdleTimer() {
+    clearTimeout(idleTimer);
+    idleTimer = setTimeout(showAttract, ATTRACT_DELAY);
+}
+
+function showAttract() {
+    document.getElementById('intro').classList.add('hidden');
+    renderAttractLeaderboard();
+    document.getElementById('attract').classList.remove('hidden');
+}
+
+function showIntro() {
+    document.getElementById('attract').classList.add('hidden');
+    document.getElementById('intro').classList.remove('hidden');
+    startIdleTimer();
+}
+
+function renderAttractLeaderboard() {
+    const board = loadLeaderboard();
+    const tbody = document.getElementById('attract-rows');
+    tbody.innerHTML = '';
+
+    if (board.length === 0) {
+        tbody.innerHTML = `<tr><td colspan="3" style="color:#555;text-align:center;padding:16px">No scores yet — be the first!</td></tr>`;
+        return;
+    }
+
+    board.forEach((entry, i) => {
+        const tr = document.createElement('tr');
+        if      (i === 0) tr.classList.add('rank-1');
+        else if (i === 1) tr.classList.add('rank-2');
+        else if (i === 2) tr.classList.add('rank-3');
+        const medal = i === 0 ? '🥇' : i === 1 ? '🥈' : i === 2 ? '🥉' : i + 1;
+        tr.innerHTML = `
+            <td class="rank-num">${medal}</td>
+            <td style="text-align:left">${escapeHtml(entry.name)}</td>
+            <td style="text-align:right">${entry.score}</td>`;
+        tbody.appendChild(tr);
+    });
+}
+
+function dismissAttract() {
+    if (!document.getElementById('attract').classList.contains('hidden')) {
+        showIntro();
+    }
+}
+
+document.addEventListener('keydown', dismissAttract);
+document.addEventListener('click',   dismissAttract);
+
 function startGame() {
+    clearTimeout(idleTimer);
     gameStarted = true;
     document.getElementById('intro').classList.add('hidden');
 }
@@ -229,10 +285,10 @@ function gameLoop(ts) {
 }
 
 // ─── Boot ────────────────────────────────────────────────────────────────────
-// Fill dynamic value in intro text
 document.getElementById('intro').innerHTML =
     document.getElementById('intro').innerHTML.replace('${MAX_DOCKS}', MAX_DOCKS);
 updateHudBest(topScore());
+startIdleTimer();
 initAnchors();
 updateCystinstein();
 requestAnimationFrame(gameLoop);
diff --git a/sys_digger/index.html b/sys_digger/index.html
index 604e77e..df67dd0 100644
--- a/sys_digger/index.html
+++ b/sys_digger/index.html
@@ -137,6 +137,62 @@
         }
         #start-btn:hover { background: #00cc66; transform: scale(1.04); }
 
+        /* ── Attract / highscore screen ── */
+        #attract {
+            display: flex;
+            position: absolute;
+            top: 0; left: 0;
+            width: 100%; height: 100%;
+            background: rgba(0, 0, 0, 0.92);
+            justify-content: center;
+            align-items: center;
+            flex-direction: column;
+            color: white;
+            text-align: center;
+            padding: 40px 20px;
+            z-index: 10;
+        }
+        #attract.hidden { display: none; }
+
+        #attract h2 {
+            font-size: 13px;
+            letter-spacing: 5px;
+            color: #ffcc00;
+            text-shadow: 0 0 12px #ffcc00;
+            margin-bottom: 6px;
+        }
+        #attract .attract-game-title {
+            font-size: 44px;
+            letter-spacing: 6px;
+            color: #00ff88;
+            text-shadow: 0 0 20px #00ff88;
+            margin-bottom: 32px;
+            animation: flicker 2s infinite alternate;
+        }
+        #attract-table {
+            width: 360px;
+            border-collapse: collapse;
+            font-size: 16px;
+            margin-bottom: 36px;
+        }
+        #attract-table th {
+            color: #555;
+            font-size: 11px;
+            letter-spacing: 1px;
+            padding: 4px 10px;
+            border-bottom: 1px solid #333;
+        }
+        #attract-table td { padding: 8px 10px; color: #ccc; border-bottom: 1px solid #1a1a2e; }
+        #attract-table tr.rank-1 td { color: #ffd700; font-size: 18px; }
+        #attract-table tr.rank-2 td { color: #c0c0c0; }
+        #attract-table tr.rank-3 td { color: #cd7f32; }
+        .attract-hint {
+            font-size: 13px;
+            color: #444;
+            letter-spacing: 2px;
+            animation: flicker 1.2s infinite alternate;
+        }
+
         /* ── Game-over overlay ── */
         #overlay {
             display: none;
@@ -309,6 +365,22 @@
     <button id="start-btn" onclick="startGame()">START</button>
 </div>
 
+<div id="attract" class="hidden">
+    <h2>HIGH SCORES</h2>
+    <div class="attract-game-title">SYS DIGGER</div>
+    <table id="attract-table">
+        <thead>
+            <tr>
+                <th class="rank-num">#</th>
+                <th style="text-align:left">Name</th>
+                <th style="text-align:right">Score</th>
+            </tr>
+        </thead>
+        <tbody id="attract-rows"></tbody>
+    </table>
+    <div class="attract-hint">— Press any key to continue —</div>
+</div>
+
 <div id="overlay">
     <h1>CYSTINSTEIN FORMED!</h1>
     <p id="final-score"></p>