diff --git a/examples/unity-game-x402-gate/.env.example b/examples/unity-game-x402-gate/.env.example
index 00a96c7..f4dbfeb 100644
--- a/examples/unity-game-x402-gate/.env.example
+++ b/examples/unity-game-x402-gate/.env.example
@@ -1,7 +1,8 @@
 # Stellar public key (G...) that receives payment. Public — never a secret.
 X402_SELLER_ADDRESS=
 
-# Free testnet facilitator key: POST https://channels.openzeppelin.com/testnet/gen
+# Free testnet facilitator key: GET https://channels.openzeppelin.com/testnet/gen
+# (open it in a browser, or `curl`; a POST here returns 401)
 FACILITATOR_API_KEY=
 
 X402_FACILITATOR_URL=https://channels.openzeppelin.com/x402/testnet
diff --git a/examples/unity-game-x402-gate/README.md b/examples/unity-game-x402-gate/README.md
index 3eea8cd..47b17b2 100644
--- a/examples/unity-game-x402-gate/README.md
+++ b/examples/unity-game-x402-gate/README.md
@@ -112,7 +112,8 @@ Fill in `.env`:
 - `X402_SELLER_ADDRESS` — a Stellar **public** key (G...) to receive
   payment. Public only; no secret involved.
 - `FACILITATOR_API_KEY` — free testnet key from
-  `POST https://channels.openzeppelin.com/testnet/gen`.
+  `GET https://channels.openzeppelin.com/testnet/gen` (open it in a browser,
+  or `curl`; a `POST` here returns `401 Unauthorized`).
 - `PLAYER_SECRET_KEY` — only needed for `wallet-bridge-smoke`, a throwaway
   testnet secret key that will actually pay. **Never use a mainnet key
   here.**
@@ -129,6 +130,13 @@ a payment:
    Stellar) — this step is reCAPTCHA-gated and has to be done by a human in
    a browser; there's no API around it.
 
+`X402_SELLER_ADDRESS` needs to be a real account too, not just a valid-looking
+key: if you generate a fresh keypair for it (rather than pointing at an
+already-funded account), it has to be created on-chain (friendbot) and given
+the same USDC trustline above before it can receive the SAC transfer —
+otherwise `wallet-bridge-smoke` fails simulation with `HostError: Error(Contract, #13)`
+("trustline entry is missing for account").
+
 ### 2. Run the mocked test suite
 
 ```bash
diff --git a/examples/unity-game-x402-gate/scripts/wallet-bridge-smoke.ts b/examples/unity-game-x402-gate/scripts/wallet-bridge-smoke.ts
index a7a167a..25e757a 100644
--- a/examples/unity-game-x402-gate/scripts/wallet-bridge-smoke.ts
+++ b/examples/unity-game-x402-gate/scripts/wallet-bridge-smoke.ts
@@ -101,8 +101,11 @@ async function main(): Promise<void> {
     console.log(`[smoke] payment accepted. Unlocked loot:`);
     console.log(JSON.stringify(payload.loot, null, 2));
 
-    const txHashHeader =
-      response.headers.get("x-payment-response") ?? response.headers.get("settlement-response");
+    // x402 v2's settlement header is `PAYMENT-RESPONSE`, not the v1 name
+    // `X-PAYMENT-RESPONSE` (and never `settlement-response`, which isn't a
+    // real header in either version). See "Settlement Response Delivery" in
+    // x402-foundation/x402's specs/transports-v2/http.md.
+    const txHashHeader = response.headers.get("payment-response");
     if (txHashHeader) {
       console.log(`[smoke] settlement response header: ${txHashHeader}`);
       const decoded = tryDecodeBase64Json(txHashHeader);