
There’s a big secret in Round 1 of Deltarune: Chapter 3. If you manage to earn S-Rank while completing the first board, you’ll unlock a special door in the Green Room. This door takes you to a bonus area that’s similar to Round 1 and gives you much more freedom to explore. There’s an eerie presence to this extra area, and your final goal is the mysterious ICE KEY. Learn how to solve all the puzzles in the Round 1 Secret Area and how to get the ICE KEY with the full guide below.
How To Get the ICE KEY

To access the BONUS GAME — an alternate version of Board 1 — you’ll need to earn S-Rank on Board 1. After earning S-Rank, go to the S Door in the Board 1 Green Room. It leads to a strange backstage area.
- In the backstage area, go left and interact with the abandoned video game console. There’s nothing here, so go back right to find a new interaction spot. Collect the Odd Controller and return to the console. Interact again and you’ll automatically begin.
This is a seemingly empty recreation of the Board 1 adventure. There’s initially nothing you can do here.

- Where To Find the Sword: Go to the bottom level of the world. You’ll need to use the switch to reveal the HIDDEN MAILROOM in the normal Board 1 run-through. If you’ve done that, a door hatch is available in the southernmost room.
- Collect the SWORD in the underground room. Once you’ve collected it, you can attack the monsters. Defeat EVERY monster in all the screens until you reach LV3 at the top of the HUD.

Once you’re Level 3, you can now destroy cactus sprites. Go to the right-most middle screen to find two cactuses blocking a cave entrance. Go inside and defeat all the enemies here until you reach LV4 / LVMAX. This unlocks the ability to destroy palm trees. You can now fully explore the map. There are a few things you can do here now.

- At the bottom screen where Kris found the sword, there’s a path blocked by two palm trees in the bottom-left. Go there to find a bunch of cave entrances. Enter all of them then walk up to find a secret message written in black.
- To the left and right of the locked pyramid door where you started, there are additional secret doors. Enter both and walk up to find secret messages (in black, only visible when you walk across the black screen) or see a strange sprite.

Getting the ICE KEY: To exit this adventure, destroy the palm trees to the left / right of the pyramid and go up. Reach the area above the pyramid to find a red treasure chest. Open it to get the ICE KEY.
It isn’t exactly clear what the ICE KEY does at this point in the story but hang onto it and keep aiming to earn S-Ranks to discover a big secret later in the chapter.