It's hard to believe that it's been two and a half years since Undertale was the talk of the town. While pangs of early nostalgia are still easy to feel, a recent return to the underground reminded me that yes, it really was every bit as good as the hype suggested. Possibly moreso, even - it's a modern classic, which makes it quite unsurprising that its fans are still picking it apart and reassembling it in fun new ways.
Undertale's fans continue to be an industrious and driven lot, using the game's rich blend of gameplay systems and easily-written characters to piece together their own stories inspired by Toby Fox's low-fi RPG opus. Among them, a full-length Team Fortress 2-themed retelling of the tale. Step inside for a tour of this and other great free games you could play today.
It's worth noting that Undertale developer Toby Fox has been clear that he is entirely cool with fan-made derivative works, so long as they're non-commercial. Fans are free to use just about anything from Undertale (within reason) to create their own spinoffs and reimaginings in any medium, which is nice.
If there's any game to headline here, it's Overtime. Created by Team Fortress 2 mega-fan Germanpeter, it mashes together two fandoms worth of rich, silly cartoon characters and sets them loose. The Administrator's cold-blooded minion Miss Pauling plays the role of the protagonist (given free discretion to either gun down or hire anyone in her path), while the Medic stands in for Toriel, and the Engineer and Soldier get to play the roles of Sans and Papyrus respectively. Somehow, it works, and many of the jokes are legitimately funny - even moreso if you're well acquainted with the TF2 cast.
It's no surprise that Overtime is imperfect, of course. Many of the attack patterns bank more on visual reference than gameplay value. Plus, the cameos from a variety of YouTubers fall somewhat flat, but it's an impressive and strange piece of work. As with the original, there are full pacifist and genocide routes, plus some hidden content added in later updates which takes the game even further afield. You can grab Overtime on Gamejolt here.
While Overtime may be the biggest finished project to date, my favourite unfinished fan-game has to be Undertale Yellow. A prequel to the original game, putting you in the shoes of one of the earlier children that fell into the underground world of monsters. This time you're the gun-slinging bearer of the yellow soul, which some hidden text in the original confirmed to hold the power of Justice, with a capital J.
While Yellow starts off in familiar enough environments, the plot quickly diverges and takes you down a new path, meeting new monsters and experimenting with new gameplay mechanics and doing some very clever things with the combat engine. It's highly reactive as well, so even the one-zone demo is replayable. The second zone - Snowdin - is apparently not too far from release now, as you can see in the trailer above, although as with any fan-project, it'll be done when it's done. You can grab it via Gamejolt here.
Going off on a wild tangent into other genres, we also have the Clickertale games. Obviously not as story-driven as the works above, but entertaining for their sheer variety of encounters and some quite playful full-screen, mouse-driven takes on Undertale's normally constrained combat engine. It's a patchy, messy thing, but there's clearly a lot of enthusiasm behind it, and Clickertale 2 (you can play the first, but the sequel largely supplants it) still semi-regularly recieves updates and new content.
Just be warned that Clickertale 2 shares a genre with the likes of Cookie Clicker. You will wear a hole in your left mouse button if you choose to proceed, and progress will be slow and arbitrarily padded. Still, there are a surprisingly huge number of complex, scripted boss encounters, and it's interesting to see how much of Undertale's DNA survives the transition from story-driven RPG to mouse-demolishing timewaster.
Honourable mentions go to two things that just don't fit the pattern, but also share a theme. First up is The End. While not released yet - and being nearly 8 months since its last development blog or trailer - I still hold out some hope that this very impressive looking fan-game completes its long gestation and is released into the wild. You can follow the project here on Gamejolt.
The End is intended to be a very long-form interactive epilogue to fan-webcomic Dreemurr Reborn, which builds on a theoretical alternate ending to the game. The comic is worth reading for the time being, and as you can see in the trailer above, not a single corner is being cut. The length of time the developers have been silent has me worried, but I've seen fan-games fall into hibernation for longer and still wake up. Fingers crossed.
Lastly, a nod to - don't laugh - a piece of pure prose fan-fiction. Normally not my scene, but if you think you've picked everything from Undertale's bones, I highly recommend reading One By One by CourierNew, which I feel understands the cadence of Toby Fox's writing and his characters well enough to convincingly puppeteer the world of Undertale through one very final story arc. Just trust me on this.
This is all of course just touching the tip of the iceberg. Countless single-battle fan-games have been created through the Unitale engine, or its successor, CYF. If you've got any favourites that didn't make the cut here, by all means share them. And be nice. There are more than enough Floweys out there in the real world.