Game
MYSTERYTALE Online (Multiplayer Undertale Fan-Game)
8 days ago

MYSTERYTALE Online - June 2026 Progress Devlog


(yes, im aware its july now, but most of the devlog was written in june. oopsie!)

Greetings, everyone.

It certainly has been a while, hasn't it? Sorry about that, life got in the way. In fact, I actually visited Floppo again since last devlog and am currently dealing with a nasty cough. That said, we've still been hard at work since the last devlog and I'd like to share what we've been up to.

As always, please make sure to join the discord server (https://discord.gg/pG2qhDT3Qn) for more frequent updates, early playable beta versions and more.

I would like to quickly address a few things though. I still get comments and questions about the BETA version being restricted to the discord server. This is mainly because the game still isn't ready for a wide release - the ping for players can weirdly fluctuate, the server software still randomly crashes and the game is still lacking PvP and random encounters, features that are very important to a lot of players. The game will release on GameJolt once it is ready and we're hoping just as much as you are that this day is sooner rather than later.

With that out of the way, let's take a look at what's been happening since the last devlog.


Let's start with the main thing people like! That's forms, right? You like those? Well, please take a look at some of the forms we've added since the last devlog.

Starting off, Legacy's PvP star, Undyne, has made her debut in MTO (again)!

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While there's no PvP (yet) for her to be the meta in, she still has her badass armour.

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Related to Undyne, a fan-favorite character from Waterfall and also Deltarune Chapter 4 has joined the game finally!

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He actually walks like a Paper Mario character, having two separate back-facing sprites, one diagonally left and one diagonally right. Though his portraits and poses aren't finished, he's already become a very welcome addition on the BETA servers.

A small, but fine addition that was requested a few times; it's Chara from TS!Underswap and our third variant of this character.

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Here's one for all you enjoyers of gay monochrome people! It's Loop from In Stars and Time, joining as the game's second rep!

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A decently popular pick in MTO Legacy, Annoying Dog was re-added, now with new poses and a drivable toy car.

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Everyone's favorite transgender cat doll ghost, Papyrus (formerly known as Mad Mew Mew) has been added! All 3 dresses included!

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We brought back DIO, also. Though right now he's virtually unchanged from MTO Legacy, barring the ability to make his pose face either left or right.

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A slightly more obscure addition from the Mario series, it's Starlow from the Mario & Luigi series!

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Another slightly deeper cut from the Mario RPG spin-offs, Geno from Super Mario RPG has also joined the game!

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Muffet finally made the leap from Legacy as well, now with new voices and poses!

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One feature I had always wanted in MTO Legacy was a seasonal events system - something where there'd be extra christmas decorations and the like around christmas or other interesting days and events. Well, I'm happy to see that I've finally added a system like this to MTO, and to kick us off, we have our first seasonal event added to the game....

Pride Month!

That's right! MTO is officially celebrating pride month! And this system is automated, so it will automatically activate and deactivate based on the server's date.

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During Pride Month, Snowdin Town will have various LGBTQ+ pride flags placed around town, along with helpful NPCs that will educate players on the meanings of different flags! Well, about as much as one can be educated in limited rhymes, anyway.

After pride month ends, town returns to normal, but worry not! Not all is temporary!

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We're adding pride costumes to various forms, and these are permanent additions that will remain available to all players! So far we've only added a handful, but we plan on adding more throughout the month via smaller patch-scale updates to the game.

The event was primarily directed and designed by Floppo and I think she's doing a lovely job! We plan on having all sorts of appropriate pride costumes so you can display your pride accordingly! We hope this event brings a lot of smiles to people in a world full of adversity.


You may have already noticed it in a few screenshots, but we actually have a brand new font for form descriptions and chat history. It is a completely custom-made font that Floppo made specifically for the game. It's pretty neat and much more readable than the old one. Of course, the old one is still used in original Undertale GUI or in places where it doesnt hinder readability too much.

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The original font was probably one of the most criticzed things about the game during earlier testing stages, so I hope everyone enjoys and approves of this change as much as we do. The font even carries over to the "small nametags" setting, which may now be my preferred way to play the game due to how much less screenspace the small nametags take up.


Those of you who have played legacy may recall the fast travel system in that game. Within Subspace, you were able to find a rainbow save point that, when interacted with, would give you the option to fast travel to any previously visited Save Point room.

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The plan has (nearly) always been to have the full Undertale map, so a good and efficient fast travel system is kind of necessary to get around well. Floppo took it upon herself to not only bring the fast travel system back, but make it much more stylish in the process!

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Functionally, it still lets you fast travel to any save point room you've previously visited. However, unlike MTO Legacy, MTO will actually feature multiple of these. We plan on expanding Subspace into a larger area that you will be able to explore and find more of these special objects, which may even take you to other worlds outright. How else would one get from Snowdin to Hometown, after all? Or, perhaps Koffin-Keep.


Though you've seen it in the screenshots, you probably forgot about the fact that we didn't really talk about the Ruins before. Floppo has been working on those for a while, actually, and I recently added the finishing touches to them, so let's take a look, shall we?

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They're basically as you remember them from UNDERTALE! Funny, isn't it? MTO Legacy only had the Ruins and a bit of Snowdin, meanwhile MTO's current development added all of Snowdin first and then the Ruins.

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That said, the Ruins aren't exactly like their version from MTO Legacy. For starters, they have a brand-new theme now! I'm told it uses a very wacky time signature! (Note from Floppo: It's 13/8!)

There are a few more changes than just that..

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Previously, the only functional puzzle in Legacy were the cracked floor puzzles - and even those were only functional to the extent of the floors cracking beneath you like in Undertale. However, now all the puzzles are functional! Well, except the "middle road" one. I'm not actually sure why we didn't bother making that one functional, but it isn't. The rest are though!

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It also means the niche room that's only accessible by failing the perspective puzzle is now actually reachable in the game! ...hooray?

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Toriel's house is also back, and of course the mirror is here too! But would you believe me if I said that even the mirror has been upgraded from it's legacy counterpart?

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Some forms (like ones actually playable in Undertale and Deltarune, games that normally don't mirror your sprites) don't have their sprites mirrored, forms with asymmetrical designs do get mirrored and then yet other forms have completely unique reflections altogether. A few even have unique interaction text for the mirror! Quite a lot of detail for such a small little thing that's just kinda off in the corner.

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The lamp in the kids room is also fully functional and synchronized between players! Even if you leave the room and re-enter it, it'll be in the state it was previously in!

There are a few other changes and plenty of new interactable dialogue, but I don't want to spoil every last thing for you. I can't wait for you guys to look for these things yourselves!

But, there is one more notable thing that not only affects the Ruins, but also Snowdin...


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That's right, puzzles are now also synchronized! Solve puzzles for others so they don't have to bother, make your friends solve them for you or just impale people on spikes for fun (Susie approved)! Of course, like before, puzzles can be bypassed from the other side so they don't act as one-way gates.

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Ice is also finally functional! Yippe!


Let's talk about a few smaller changes and improvements for a moment.

Crossbones and TS!Underswap Papyrus received complete redesigns using their original TS!Underswap sprites.

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Their legacy counterparts are still available as optional costumes for those who prefer them.

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The change was made due to the fact that the FH!StoryShift characters already use their original unedited sprites, as well as the fact that adapting TS!Underswap Chara into an Undertale sprite edit would kind of defeat the point of having them in the first place. After all, that would just be the regular Fallen Human sprite but with a neutral expression, something I think we can all agree would be less interesting. So, for the sake of consistency it was decided to have these two use their original sprites by default. They also come with plenty of new portraits and poses! Though I did have to be rather careful not to accidentally add poses that weren't already viewable via UTModTool...

In a similar vein, I've decided to re-add the legacy designs of the Swap Bros as costumes. This wasn't a recent decision or anything and was planned for a while, I just hadn't gotten around to it before.

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Although subtle (and likely hard to see on a GIF), the pulsating effect in Subspace was updated from a tilemap stretching effect to be an actual shader-based effect. Though, again, it may be hard to tell from the GIF, the effect is much nicer than the old one when viewed properly in-game.

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There's also a new feature that allows you to turn without moving by holding ALT. Despite being a small thing, it unironically has a huge effect and people use it all the time.

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Floppo redesigned UnderNet's UI to be much more pleasant to the eye!

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I made moderator actions get logged to UnderChat, similarly to Legacy.

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In a lot of UT/DR online multiplayer fan-games (weird how there's been quite a few over the years, huh?), players who are in a battle would be invisible to other players. This is due to the fact that those games would typically directly mark the player as being in the exact room that's currently loaded, with the battle screen typically being a separate room.

I never actually liked that weird disconnect, which is why in the 1.0 Beta of Legacy I made a push to change that. This is also in the new versions of the game too, but was accidentally broken when we released 0.1 to our Discord server. It has since then been fixed.

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We're also actively updating the content that's already in the game, adding new costumes, portraits, voices and poses to various different forms. I won't show off all of these, but here are a few:

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Completely unrelated to the person depicted above, but do you think Riverperson is genderfluid because they hang around water all day?

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There's a lot more that we've done, including a lot of internal changes to the code that can't be easily shown off in screenshots and the like, but the game is coming along nicely, rest assured.

Once again, you can join the Discord server to gain early access to new versions of MTO.

Now, I initially wrote this devlog before the release of Deltarune Chapter 5. But due to procrastination, I didn't finish it! Oopsie! Regardless, yes, about most of the things from Chapter 5 that you would want to see in the game are, in fact, planned.


There is one more thing I'd like to show off. Floppo really wanted to create a character for the game to serve as somewhat of a mascot. And she ended up creating something wonderful.

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This is 😐︎⌛︎ (pronounced KASIX). I had first introduced them on the 9th anniversary stream. They will be the playable character in the singleplayer side-story, though they are already available as a form in the main game.

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They've already found their footing as a relatively popular character in the game! Originally, we had considered holding off on them being available until the singleplayer side-story was far enough in development for people to get a proper understanding of who they are, but due to people already growing fond of the design, we decided to make them available to players early!


Though she's currently working on other things, the next thing Floppo intends to do is add most of Legacy's skins into the game as forms - barring a few exceptions of characters that are being scrapped. For those curious, Paper Mario, Dell and Jane are going to be changed into costumes for regular Mario, Engineer and Soldier respectively, as opposed to standalone forms. Rick and Morty are being scrapped outright, as they're far too tonally dissonant with the game. Aside from that, Floppo does also really want to get working on Waterfall.

Originally, I was hesitant on having new major areas be added beyond Snowdin for the time being, due to, well, the actual content for Ruins and Snowdin (i.e. encounters, cutscenes, etc) not even being implemented yet. But I've thought of a compromise where save data will just be partially reset in order to prevent sequence breaking (or any other forms of game breaking that could result from this), but not fully.

As for myself, outside of working on bug fixes and general improvements, the main feature I intend to work on is a fully finished UnderNet system, along with additional social features that tie into that (i.e. friends system and blocking). UnderNet will not be a fully fledged social media platform, of course, but you will be able to set up a profile and post basic statusses that other players can see even when you're offline. UnderNet will additionally come with a player list that allows you to see the exact rooms players are in - with the option to only show this information to friends or hide it outright. This will be necessary with how big the map is getting, as otherwise you'd be hardpressed to find other players.

After UnderNet, I can focus on another very unique feature; the party system. You'll be able to team up with other players and engage in battles together! While I don't want to say too much about that just yet, I think that's definitely going to be a major feature. Once that's been implemented, I can finally start work on the PvP system. The reason I have to implement the party system first though is so there's proper infrastructure for me to implement teams into PvP, a major new addition to the PvP system I've wanted to add for a long time.

Regardless, I apologize for the infrequency of devlogs lately, but I assure you that development is coming along nicely.

Hope to be seeing you all soon!



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