The coveted Ice Key isobtained by successfully completing a secret minigame that becomesaccessible after the conclusion of the first round of Tenna's game showin Deltarune Chapter 3. This particular minigame is locked away inside a special room, which is exclusively available to contestants who achieve an S-rank. To earn this distinguished rank and gain entry to the room, you will need to accumulate a score exceeding 1500 points during the initial "Zelda-style adventure" minigame segment.
After you have triumphantly secured an S-rank on the first part of Tenna'sgame show, your next step is to make your way into the designated changing room that is conspicuously marked with a large, bold "S" on its front. Thischanging room, upon entry, reveals itself to be a rather unadornedhallway, sparsely furnished with a vending machine and a collection ofpeculiar non-player characters (NPCs). Engage in conversation with thecharacter standing directly in front of the door located on the leftside of this hallway; they will inform you that there are even moregames awaiting your challenge within the room behind them.
Proceed inside this newly accessible room, then turn left and interact with the old game console situated there. The console will display a message indicating that yourequire a controller. To resolve this, simply exit the room, and youwill find a suitable controller lying on the groundnearby, ready for you to pick up. Once you have acquired the controller, return to the game system and connect it. Upon successful connection,you will be instantly transported back into the 2D "Zelda-style"minigame, but with one critical difference: you will be without your party members. The cave that previously housed a shop in this minigame area will nowfeature a message ominously urging you to "Become Stronger."
To advance through this solo challenge, you must navigate all the way to the southern edge of the map and then make your way underground into the "mail room," an area youmight have briefly discovered during Tenna's main show. Inside this mail room, you will find a crucial sword. Acquire this weapon, and then systematically defeat every single enemy present within the minigame's environment. This concerted effort will provide you with precisely enough XP to reach level three. At this newfound strength, you will unlock the valuable ability to chop down cacti. Head east and use your sword to slice through the two cacti that areblocking a previously inaccessible path, allowing you to continue yourprogression.
(A helpful note forthose concerned about their in-game alignment: these spectral "ghostenemies" encountered within this minigame do not count as true killstowards a pacifist run!)
Upon advancing past the cacti, you will find yourself in a new, eerie area enveloped in a pervasive purple haze. Continue your methodical "slaughter" of the remaining enemies until you reach max level. Having attained this pinnacle of strength, you are now capable of chopping down trees. Return to the main minigame area and begin cutting your way through the dense forest. The direction you choose to clear a path is not critical. After moving through a few screens, you will finally discover atreasure chest containing the invaluable Ice Key. That's all there is to this particular segment of your secret quest!
At this juncture, you are free to continue with Tenna's game shownormally. Earning additional S-ranks in subsequent rounds will unlockfurther secret minigames within this hidden back room, each rewardingyou with even more rare and crucial items. These collected items are all absolutely required to access a distinct alternate story path at the very conclusion of Deltarune Chapter 3. Therefore, it is highly advisable to create a save file at key points,just in case you fail to score enough points during an upcoming roundand need to attempt it again. While this alternate route may not be asdramatically transformative as Chapter 2's infamous "Snowgrave route,"it nonetheless offers a significantly different experience from thestandard sequence of events, providing a unique and rewarding narrativedeviation for dedicated players.