“I will make another. I am making a game called “DELTARUNE.” It is the second game in the UNDERTALE series.”
– Toby Fox¹⁾

Undertale and Deltarune are two different role-playing games that was developed by Toby “Radiation” Fox. Undertale began as a demo in 2013,²⁾³⁾⁴⁾ raised $51,124,⁵⁾ and released in full on September 15, 2015,⁶⁾ with ports for the PS4,⁷⁾ Switch,⁸⁾ and Xbox One⁹⁾ coming much later.

On the other hand, Deltarune is a spin-off game in development that has had content-filled demos surface in 2018¹⁰⁾¹¹⁾ and 2021.¹²⁾ The seven chapter project actually predates Undertale,¹³⁾¹⁴⁾ but was shelved. At the time of this writing, Toby Fox is planning to release the next few chapters of Deltarune on Steam and it's going to cost more than Undertale.¹⁵⁾

The story of Undertale is simple. A young protagonist wanders onto Mount Ebbot, falls into a hole, and winds up stuck underground with sealed-away monsters from a war that happened long ago. Their primary goal is to leave and return to the surface, but they also have the option to either assist or hurt these monsters along the way, which ultimately affects the ending that the player receives in Undertale.¹⁶⁾

In contrast, Deltarune follows a teenage protagonist who attends school, and finds himself becoming one of the “Heroes of Light” tasked with restoring balance to the Dark World. As the story progresses, their party finds more Dark World portals in the Light World and must close the Dark Fountains in them to restore order. Of course, at the time of this writing, the game isn't fully out yet.

Toby Fox wanted to make a role-playing game and his first project, which later became Deltarune, spans as far back as April 2012.¹⁷⁾ However, it was shelved as it was rather dark and it'd be a bad look. Instead, he started with a simple game where nobody had to die, which later became Undertale.¹⁸⁾ The first screenshots of Undertale were uploaded as a sort of joke response around February 4, 2013.¹⁹⁾

Later that year, Fangamer streamed the Undertale demo,²⁰⁾ which became public after three weeks,²¹⁾ and the Undertale crowdfunding campaign began, asking for $5,000 but raised $51,124 instead.²²⁾ While the campaign suggested that Undertale was slated for a Summer 2014 release, it ended up being quietly delayed to September 15, 2015²³⁾ and it blew up!

Coming off a huge success, Toby Fox resurrected his first project, nervously²⁴⁾ completing a playable demo of Deltarune and publishing it on October 31, 2018.²⁵⁾²⁶⁾ After this, he acquired a team, made significant progress, but also suffered from wrist pain.²⁷⁾ Then in 2021, for the 6th anniversary of Undertale,²⁸⁾ he would generously unveil a second demo of Deltarune that released on September 17, 2021.²⁹⁾³⁰⁾

• In the past, Toby “Radiation” Fox was known for ROM hacks of EarthBound,³¹⁾ which he tried to scrub evidence of,³²⁾ and being apart of the Homestuck music team per Bill Bolin's suggestion.³³⁾
  • According to The Making of Radiation's Halloween Hack,³⁴⁾ “Megalovania” had been inspired by “Gadobadorrer” from Brandish 2, allegedly yelling a draft into a microphone.
• I was an administrator for the Undertale Wiki on Wikia/Fandom from October 2015 to May 2016, then I chose to retire since the wiki was pretty much done and also out of caution.
  • We had an administrator that turned out to be an indie developer, but I can't remember if she did know Toby Fox and possibly advised him to be radio silent as a public figure.
  • On the “Genocide Route” naming issue, I dismissed it as misguided concerns,³⁵⁾ but several people were really convinced that the word “genocide” was specific as the word “shoah”.
    • If people proposed a better antonym (e.g. “Warhawk”) or system (e.g. “Merciful” & “Merciless”), then I would've been more open. “No Mercy” was just a bad suggestion.
• There was a lot of “backseat gaming” when Undertale was starting to gain traction as streamers would forget or didn't hear the trailer's message of “the friendly RPG where nobody has to die”.
• From March 2016 to August 2017, Undertale once had an unofficial Japanese translation patch.³⁶⁾ Its most notable volunteer was the Hatoful Boyfriend author, Hato Moa.
  • Flowey's “that's a wonderful idea!” line was dubbed into Japanese by Toby Fox in the localization,³⁷⁾ translated as “nante suteki na aidea!” (なんて素敵なアイデア！, lit. “what a lovely idea!”).
  • The patch used a normal font for Sans and Papyrus, while the localization has Sans using “Happy Luika” (ハッピールイカ) and Papyrus using “Tanuki Yusei Magic” (たぬき油性マジック).
• Several enemies in the “School Dark World” of Deltarune were borrowed from playing cards that were illustrated by Kanotynes,³⁸⁾ which was reblogged by Toby Fox in the month of April 2012.³⁹⁾
• An unused, dice-themed enemy named “Pippins” appears in Chapter 1's pacifist ending, despite him being cut, and the Party Dojo. Toby Fox reveals that he was left out as his battle wasn't fun.⁴⁰⁾
• This is probably an oversight, but Malius does not give the option to repair Spamton's Broken Sword.

The “Thrash Machine” (ボコリングマシン, Bokorin Mashin) is a machine in Chapter 1 of Deltarune that the protagonist can design and gets blown up, but it does make a return in the normal route for Chapter 2 as a boat and later affects the protagonist's mecha in the true final boss fight, so I've made a chart organizing the data with images of the “optimized” build for each characteristic.

		ELEGANT エレガント	LIVELY スポーティ	CUTE キュート	HOT ホット	COOL クール	GUN'S ＧＵＮ
HEAD	LASER レーザー					★	★
	SWORD ソード	★	★
	FLAME フレイム			★	★
	DUCK アヒル
BODY	PLAIN ノーマル	★		★
	WHEEL ホイール		★			★
	TANK タンク				★		★
	DUCK アヒル
SHOE	SNEAK スニーカー		★	★
	A.WHL Ａ．ホイール				★	★
	TREAD キャタピラ	★					★
	DUCK アヒル
OPTIMIZED
		★★★★★★	★★★★★★	★★★★★★	★★★★★★	★★★★★★	★★★★★★

For people with sharp eyes, you will notice that the design in the default Chapter 2 new game file is the same design as the gun-optimized design seen here, but with different colors.

• UNDERTALE and DELTARUNE - The official websites for Undertale and Deltarune.
  • @undertale and @undertalejp on Twitter - The official accounts for the Undertale series.
  • @tobyfox on Twitter - Andrew? Andrew Hussie? Is that you?

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