Highlights
- Undertale fan games provide unique reimaginings and expansions of the original game, offering players new stories and gameplay experiences.
- Memory, Atonement, and Underfell are some of the best Undertale fan games available, each offering their own unique twists on the original game's story and mechanics.
- These fan games often feature expanded dialogue, challenging puzzles, and additional characters with their own lore.
One of the most beloved indie games of the last decade, Undertale still inspires fans to create unique reimaginings and expansions of the original game by Toby Fox. Fans will recognize most games on this list, but one didn't make the cut: Overtale.
Unfortunately, development on this game stalled out, but the rest of the games on this list are playable now, some right from your browser. Explore new tales about Sans, Toriel, Frisk, Chara, and all the other monsters from Undertale. Bonus: there is even a fan game with PvP and multiplayer!
Updated July 26, 2023, by William Quick: Undertale turned out to be a huge gaming phenomenon and now creator Toby Fox is under a lot of pressure to deliver the sequel DELTARUNE. Although it's been years since Undertale's release, only two chapters of the sequel have been released. However, they do not disappoint, and they're currently free to play which is quite generous.
Even so, that Undertale itch is not an easy one to scratch, and it's hard to wait for new official content to come out. The good news is that there are many talented and dedicated fans of the series who have taken it upon themselves to create fan games using the elements to create spin-offs or tell completely new stories using very similar aesthetics. Here's a selection of some of the best ones out there to make sure you don't have a bad time.
20 Memory
This fan game features 3 routes for players, 7 endings, and 3 unique final bosses. It's also one of the few fan games that acknowledges the original Undertale story in a very meta way. Created by LUKELCS, the game even includes an original character in Bucky the Bunny.
It sticks out as one of the newest Undertale fan games as it was published in only September 2020. But perhaps the best feature of this fan game is the expanded and original dialogue paired with plenty of puzzles to keep players busy.
19 Atonement
Despite the quirk and friendliness of the characters in Undertale, there's an underlying darkness that never fully goes away. It makes use of an underlying morality mechanic which greatly affects many notable events in the game with you possibly becoming the real monster. This is reflected in the disturbing game Atonement.
You play as a character who resembles the hero Kris from the sequel DELTARUNE who has died and been cast down into Hell. After meeting with the Devil himself, you're free to roam the torturous underworld in hopes of proving that your soul is not beyond salvation. Though the character has red eyes and a creepy smile, you have to believe that you have enough power to guide them to the right path.
18 Underfell
There are many different iterations of Underfell, but this one comes from VLG Games.
This is the Undertale fan game to play if fans love unforgiving experiences like Dark Souls. The game takes place in an AU with extremely powerful and aggressive monsters. Furthermore, one wrong move on top of a trap can spell an instant game over for the player.
Fights in the game also represent significant endurance challenges as opposed to tactically different battles.
17 Undertale Red
Many fan games for Undertale feature just one epic battle with different mechanics or unique characters. For instance, Undertale Red pits the player against a character resembling a Little Red Riding Hood-themed monster sometime after befriending Undyne in the timeline.
Her attacks can cut the bullet board into a number of different pieces to complicate things. "Red" also expresses her desire to be in Undertale with some distinct lore of her own.
16 Horrortale
In the fan game Horrortale, Undyne has now become Queen after a long time of neutral rule by Frisk. Her laws cause a famine, driving the monsters mad from starvation and her own torture. Monsters now eat humans rather than harvest their souls.
The player embodies another human named Aliza who is weak and shy but has a penchant for cruelty. Though you cannot take the genocide route, the player must navigate this dark new Underground and survive. The fan comic by Sour Apple Studios inspired the game. The game, in turn, inspired fan art, too.
15 Abyss Story
Undertale captivates by plunging Frisk into an unknown world with no clear goal except to get back home. This works as an effective driving force, but the hero of Abyss Story is going as far as they've ever gone from home in hopes of finding their sister. The catch is that it may already be too late.
This is due to the fact that they need to break into the soul dimension just to continue their search. While there are a lot of interesting things and peaceful locations, this is not a realm where you want to linger lest you become part of it. It's a slow-paced adventure (still in development) involving exploration and puzzle-solving while uncovering memories that hopefully will lead you closer to your sister, or at least find out how she got here.
14 Overtime
Though there are now many games like it such as Overwatch, Team Fortress 2 pioneered what would become MOBA-type first-person shooters. With such a strong fanbase itself and iconic characters like the Medic (now Sani on the right with Sans on the left), the game makes a natural fit for a crossover with Undertale.
In Overtime, Miss Pauling travels across the Badlands to kill the Mann Brothers. Will she fight the mercenaries trying to kill her or not? The classic genocide/pacifist question still remains.
13 Don't Forget
The original Undertale is a single-player experience, but Don't Forget offers players more options. There is PvE (described as pretty grindy), but also PvP and multiplayer. With an official release last month, the game is still very much alive.
Players take on the part of Harlow who lives with the Dreemurrs (adoptive family) on the surface. Monsters and humans co-exist, but something isn't quite right. Don't Forget also employs some mechanics from Deltarune which has the first chapter available for free right now. This fan game shows off just how much story-driven games can impact gamers.
12 Disbelief
While still only about 20% completed, many fans in the Undertalk community cannot wait for Disbelief to finish mainly for its unique depiction of Papyrus. YouTuber Flamesatgames is behind the game that has Papyrus judge the player since this AU has the player take down Sans instead.
Papyrus is very powerful, but the way he tries to reason his way into fighting the player has been described as "heartbreaking." It adds another dimension to the Papyrus character and fans can't wait for the completed game to launch.
11 Everhood
Though not blatant, Undertale incorporates what could be called the creepy-cute art style, but the cute elements tend to have priority. It also has a minimal color palette to make any bright colors really stand out. In Everhood, a similar style is present with a greater emphasis on color to go along with the music focus.
You play as a character that could be a distant relative to Geno from Mario RPG wandering through a dark, twisted, and non-linear world. The objective is never fully clear, and your only drive is to find characters who have information and will more than likely challenge you to a music battle. The combat is very different from Undertale having a more rhythmic mechanic and should you die at any time, then even more mysteries are revealed to push you deeper.
10 BTS And YABTS (A.K.A Endless Sans)
Enter Bad Time Simulator and Yet Another Bad Time Simulator by Joe Zeng. You can play Sans in 3D like this YouTuber does or play Endless Sans in any internet browser right now. The reimagined boss fight goes from 2D to 3D offering a new experience for fans of the original title.
Like other classic titles including Castlevania: Symphony of the Night, Undertale features excellent music that makes every encounter unique. In BTS and YABTS, the original soundtrack appears, as well, so you can create new bad memories of the epic Sans boss fights with great music.
9 Undercards
If fans don't want a multiplayer experience but still want an Undertale-inspired game with different mechanics, look no further than Undercards.
Available on their website and even on the Google Play Store, Undercards employs characters, items, and more from the original game. This is also one of the most supported and popular fan games by far with support for community chat and friends lists. There is even a ranked mode with monthly seasons and rewards.
8 INK Sans
Described by some as the ultimate Sans battle, this one-fight-only fan game has the player trying to go for a genocide run whilst being thwarted by not one, but many different Sans characters.
Each Sans that joins the fight adds new challenges for the player from lasers to cleavers to bones and more. The only gripe some fans have about it is that there is only one song for the fight. Be warned: it is for gamers who want an extreme challenge.
7 Bad Monday Simulator
Sans is often seen as a lazy and apathetic character who just wants to relax and be left to his own devices. However, more info reveals that he's much more aware and powerful than he ever lets on which makes his boss fight extremely difficult and memorable. So much so, that his battle has been recreated as Bad Monday Simulator.
Hating Mondays is nothing new and Garfield has been saying it for years which is why he's the face of this game. You'll enter a duel with a god-like being that is a combination of the famous lasagna-loving feline and arguably the star of Undertale. It's an endurance match whether you're on the offensive or defensive so be sure to be in a chill headspace to take it on. It's also surprisingly fleshed out with multiple difficulties and endings for each one.
6 Understory
Some fans have described Undertale as one of the hardest games ever. Others who might skip games like Dark Souls will favor this fan game that focuses more on lore with a little twist on the fighting mechanic from the original game. Like Horrortale and Don't Forget, Understory features a human player character in a setting post a True Pacifist Undertale run. The story also features a human other than Frisk or Chara. However, humans and monsters are still at war with each other.
As a young boy named Nick, the player falls into the Underground to find that monsters have lost faith in all humans. To quote Fred the Gladiolus, "In this world, it's kill or be killed."
5 Dust Tale
A favorite among fan games, Dust Tale imagines a dark future for the monsters where Chara has initiated an endless genocide run. The player cannot control the human actions and must watch as Chara slaughters all in their path. But the story isn't so bleak: Sans remembers it all. And he wants to stop the cycle.
The inversion of the lore with the faithful level of remaking also includes a reimagining of the classic soundtrack for even more atmosphere.
4 Undertale Green
In this prequel fan game, the human soul of Kindness named Cody falls into the Underground much like Frisk does. He must aid Undyne in figuring out why this mysterious virus is spreading throughout the monsters. With five chapters in total, chapter three of Undertale Green was released in April of this year.
But in a big difference from the original game, monsters bleed upon genocide. The developers have said that this has plot relevance in future chapters. Fans can check out some of the boss fights here.
3 DELTATRAVELER
Every Undertale fan is excited for DELTARUNE and so far only two chapters have been released with no telling when the next one is coming out. We already love the story, the characters, and the new mechanics, but there's not enough to satisfy. For another taste, you can check out DELTATRAVELER.
This game puts you back into the roles of the lovable duo consisting of the human Kris and the monster Susie. The story is that they're not in Kansas anymore... or even in their own Undertale dimension! They've fallen into the original underground and luckily Noelle is down there with them. The trio needs to work together to make their way through a lot of familiar locations and monsters to get back to their world.
2 Unfair Undyne
Joe Zeng didn't stop with BTS and YABTS when it comes to Undertale fan games. The commitment to crazy boss battles and intentional bad times continues in Unfair Undyne or NGAHHH! Simulator. Though she might have become Queen this time, Undyne still calls the shots here.
Available from your browser, this fun rhythm game offers a challenge players can take on whenever and wherever. Be aware that, as other gamers have noted, it can get frustrating. After all, the player only has four health regardless of the game level. With the original Undertale having made the jump to switch a while ago, gamers can keep their fingers crossed for these titles which should be joining Undertale soon.
1 Dylantale
Though development on this fan game is not ongoing, it remains one of the most notable and favorite among fans. Dylantale takes a page from the "slice of life" genre in that the player controls Dylan: a yellow blob who desperately needs to get an A+ to get his mom off his back. It still includes "Pacifist" and "Genocide" runs, but instead of monsters and humans, the world has "Failures" and "Not Failures."
With many traits that make it unique, Dylantale reminds people why indie games can explode into cult classics overnight. See all the blobby goodness and test anxiety in YouTuber LiNX 4's video.