Chapter 2 of Toby Fox’s Undertale sequel, Deltarune, just dropped very suddenly and the internet exploded. As we said before, Undertale wouldn’t be Undertale, and thus Deltarune wouldn’t be Deltarune, without its fair share of secrets. Much like the Chapter 1 secret boss, Jevil, Chapter 2’s secret boss requires you to jump through a ton of hoops throughout your play through just to find him, though defeating him grants you significant rewards.
Step 0 (Optional): Recruit the Hacker
You don’t actually have to do this, but it makes another step significantly easier. In the Cyber Fields you will find a snappy dressed cursor who calls himself The Hacker. He wants you to find three blue checkmarks throughout the fields.
The first can be found in a treasure chest in the southern part of the fields, where you first meet Tasques. You’ll also find a GlowWrist in the same chest.
The second can be found at the top of the middle teacup ride in the room with three teacup rides. You will have to gather 16 arrows to successfully make it to the top.
The final checkmark can be obtained by completing the final word puzzle. You will have to spell out the world GIASFELFEBREHBER by stepping on floor switches.
After obtaining these three checkmarks you can go back to the Hacker to recruit him. He will now aid you on the rest of your journey.
Step 1: Take Spamton’s Deal
Halfway through the game you will fight a very peculiar and very creepy boss named Spamton. Don’t fight him directly. Instead, attempt to spare him by hearing out all his dialogue and eventually choosing to accept his deal. The battle will end and he will take up shop in the Trash Zone, to the left of the teleporter behind a previously locked door.
Step 2: Talk to Spamton and Buy the Keygen
Visit Spamton’s shop later in the game, after the teleporters open up when you get to the mansion. He’s as creepy as ever. Talk to him and choose every dialogue option. Make sure to choose the yellow options that unlock too. He will tell you about a dark room at the bottom of the mansion.
Buy the Keygen from his shop. The prices change every few seconds so wait for it to be cheap enough to afford. I got mine for 62 “Kromer.”
Step 3: Find the Secret Castle Basement
As you progress through the game, you will eventually come to stairs leading to the second floor of the Queen’s mansion. To the right of these stairs is the most difficult traffic puzzle in the game. It asks you to hit multiple switches with quick timing to keep traffic frozen.
Getting through this puzzle will lead you to a secret storage room. There is a hidden switch in the right pillar of a set of pillars surrounding a teacup. This might be hard to find considering the room is so cluttered with garbage. Luckily, if you recruited the hacker he will help. He will walk across the room left and right and when he overlaps the pillar you need to check, his cursor will turn into a finger! Convenient!
Checking the pillar will open a passage to the south. Take the passage. Use the Keygen on the lock to the right. Congratulations, you’ve found the Secret Dungeon, the Castle Basement.
Make sure to hit the switch to the left as well for easy travel back to the Mansion’s shops and save point.
Step 4: Find the Empty Disk and Give it to Spamton
Your next task? Get through the basement. It’s a pretty straightforward dungeon. The hardest part is a teacup ride with a bullet hell sequence which is easily the hardest in the game. You’ll find a switch, deactivate a force field, and eventually find an old robot with a shining point in its face. Examine it and you’ll get the EmptyDisk.
Now it’s time to head all the way back to Spamton. Present him with the disk and he will download himself onto it. Note, this closes his store for good.
Return to where you found the disk and examine the robot again. You’ll put the disk inside and for a while nothing will happen.
Try to leave the dungeon, though, and the secret boss fight will begin.
Step 5: Good Luck!
Spamton NEO is by far the hardest enemy in Chapter 2. You’ll actually be able to fire bullets from your heart this time (similar to the Metaton fight in Undertale) and you’ll have to put all your bullet hell knowledge to good use.
You get two different rewards for either sparing him or killing him, both of which are some of the best equipment in the game.
Sparing him will get you the Dealmaker, an incredibly powerful armor that increases the cash you earn in battle by 30%.
Killing him gets you the Puppet Scarf, an incredibly powerful weapon for Ralsei.
You’ll also get a ShadowCrystal, something you get for encountering and defeating every secret boss of every chapter. So make sure you get Jevil’s too.