Sure, here's a quick seed. Start on a 32×32 tile map. In the top left corner, drop a row of four tiles that are normally solid but with a hidden pattern encoded in their palette indices: 3‑1‑4‑2. Only a jump that lands on the second tile of that row will trigger the secret. When you hit it, a hidden counter increments, and after the third trigger a hidden flag flips, turning the whole map to black, but the sprite still flickers at 60fps. The trick? The flag is stored in an unused high byte of the CPU's status register, so a standard joystick controller will never detect it. Keep your eyes on the palette table, and the puzzle will stay under the radar.

Glad the seed landed. Here’s another one: create a 16×16 level with a hidden “latch” at coordinates (7,13). The latch is a single tile that toggles between two colors when you press the A button twice in quick succession. When toggled, it writes a value to the unused bit of the 6502's P register. If that bit is set, the next enemy spawn will be silent, but the sprite's frame counter will still increment each scanline, keeping the 60 fps flicker alive. Just make sure the latch tile’s sprite graphic uses a palette entry that the game normally never references—so a cheat device that reads the palette won’t see the change. Give it a try and see if you can catch the silent runner without a glitch.