Undertale Red and Undertale Yellow represent significant expansions to the beloved indie RPG Undertale, offering new storylines, characters, and gameplay mechanics. These fan-made projects, often referred to as “fangames,” are built upon the foundation of the original Undertale but branch out into distinct narratives and experiences. While not officially released by Toby Fox, their development and availability have garnered considerable attention from the dedicated Undertale community. This guide will walk you through the process of acquiring and installing Undertale Red and Undertale Yellow, ensuring you can dive into these captivating new adventures.

Understanding Undertale Red and Yellow
Before delving into the installation process, it’s crucial to understand what Undertale Red and Undertale Yellow are and how they differ. Both are independent projects developed by fans, aiming to capture the spirit and gameplay of the original Undertale while introducing fresh content.
Undertale Red: A Glimpse into the Unknown
Undertale Red, often referred to as “Undertale: Red,” is a fangame that explores a narrative and setting that complements the original Undertale. While details can vary as development progresses, it typically focuses on a different perspective or a previously unseen part of the Underground. Players can expect the signature blend of bullet-hell combat, character interactions, and branching narrative choices that define the Undertale experience. Its development has been ongoing, with various playable builds or demos released to the public, allowing fans to experience its evolving story and mechanics.
Undertale Yellow: A Prequel Adventure
Undertale Yellow stands out as a prequel to the events of Undertale. This ambitious project aims to shed light on the backstory of the Underground, the characters who inhabit it, and the history of the monster-human war. Players will experience the journey of a human child who falls into the Underground before the events of the original game, interacting with characters whose origins are hinted at in Undertale. Undertale Yellow has seen significant development and has had a more complete, playable version released to the public, making it a popular choice for fans eager to explore the lore of the Undertale universe.
Acquiring Undertale Red and Yellow
The acquisition of Undertale Red and Undertale Yellow typically involves downloading them directly from their respective official project pages or trusted fan community hubs. Unlike commercial games, these fangames are usually offered as free downloads.
Locating Official Project Pages
The most reliable method for obtaining these games is to find their official development pages. These are often hosted on platforms like Game Jolt, itch.io, or dedicated forums managed by the development teams. A quick search for “Undertale Red official page” or “Undertale Yellow download” should lead you to these primary sources. Be cautious of unofficial download sites, as they may host outdated versions or, in rare cases, malicious software. Always prioritize links that appear to be directly associated with the game’s creators.
Downloading the Game Files
Once you’ve located the official page for either Undertale Red or Undertale Yellow, you’ll typically find a download link. The files are usually compressed archives (e.g., .zip, .rar, .7z). The download size can vary depending on the build or version of the game, but generally, they are manageable. Ensure you have sufficient free space on your computer’s hard drive before initiating the download.
Verifying Download Integrity
After the download is complete, it’s good practice to check the integrity of the downloaded file. If the download is incomplete, the archive may be corrupted, leading to installation issues. Most download managers and web browsers provide file size information, which you can compare against the stated file size on the download page. Some project pages may also provide checksums (like MD5 or SHA-256) that you can use with specific tools to verify the file’s integrity.
Installing Undertale Red
The installation process for Undertale Red, like most Undertale fangames, is usually straightforward and often does not require a complex setup wizard.
Extracting the Game Files
Most Undertale fangames are distributed as self-contained archives. After downloading the .zip, .rar, or .7z file, you will need to extract its contents to a desired location on your computer.
- Windows: Right-click on the downloaded archive file. Select “Extract All…” or use a third-party compression utility like 7-Zip or WinRAR to extract the files to a new folder. Choose a location that is easily accessible, such as your Desktop or a dedicated “Games” folder.
- macOS: Double-click the downloaded archive file. macOS has built-in support for extracting .zip files. For other formats like .rar, you might need to use a third-party utility.
- Linux: Depending on your distribution, you can usually extract archives via your file manager or by using command-line tools like
unzipor7z.
Locating the Executable File
Once the files are extracted, navigate into the newly created game folder. Inside, you will look for an executable file. This file typically has a .exe extension on Windows and might be named something similar to “Undertale Red,” “Game,” or a variation thereof. On macOS and Linux, the executable might not have an extension but will be identifiable as an application file.
Running Undertale Red
Double-click the executable file to launch Undertale Red. If the game is designed to be portable, it will run directly from the extracted folder without needing a formal installation process. Some fangames might have accompanying data files or folders that need to remain in the same directory as the executable for the game to function correctly.

Troubleshooting Common Installation Issues
- “Missing DLL” errors (Windows): This usually indicates that certain system libraries are not present on your computer. Often, these are related to the framework the game was built with (e.g., .NET Framework or Microsoft Visual C++ Redistributable). Check the game’s download page or accompanying README files for any specific runtime dependencies that need to be installed separately.
- Game not launching: Ensure you have extracted all files from the archive. Sometimes, essential data files are missed if the extraction is incomplete. Also, try running the executable as an administrator by right-clicking on it and selecting “Run as administrator.”
- Antivirus flagging the executable: It’s not uncommon for antivirus software to sometimes flag executables from smaller, independent developers as potential threats due to their nature. If you trust the source of the download, you can usually create an exception in your antivirus settings for the game’s executable or folder.
Installing Undertale Yellow
Undertale Yellow follows a similar installation pattern to Undertale Red, often being a direct executable or requiring simple file extraction.
Extracting the Game Files
As with Undertale Red, download the game archive for Undertale Yellow. Once downloaded, extract all contents of the archive to a preferred location on your computer using the methods described previously for your operating system.
Identifying the Game’s Launcher
After extraction, open the game’s folder. You will be looking for the primary executable file that launches Undertale Yellow. This is typically named after the game itself or a generic “Game.exe.”
Launching Undertale Yellow
Double-click the executable file to start Undertale Yellow. If the game requires a specific configuration or has associated data files, ensure they are all present in the same directory as the executable.
Running Undertale Yellow on Different Platforms
Undertale Yellow has been developed to be playable on multiple operating systems, including Windows, macOS, and Linux.
- Windows: Download the Windows version and follow the extraction and execution steps.
- macOS: Download the macOS version. After extracting, you may need to right-click the application and select “Open” if you encounter security warnings.
- Linux: Download the Linux version. Depending on the distribution, you might need to make the executable file runnable. You can do this via the file manager’s properties or by using the command
chmod +x <executable_name>in the terminal, then running it with./<executable_name>.
System Requirements and Optimizations
While Undertale fangames are generally not resource-intensive, it’s wise to check for any listed system requirements on the download page. Most modern computers should run them without issue. If you encounter performance problems:
- Close background applications: Free up system resources by closing any unnecessary programs running in the background.
- Lower in-game settings (if available): Some fangames might offer graphics or display options that can be adjusted for smoother performance.
- Update graphics drivers: Ensure your graphics card drivers are up to date, as this can sometimes resolve performance bottlenecks.
Exploring the Undertale Lore Through Fangames
The availability and ease of installation for Undertale Red and Undertale Yellow allow the vibrant Undertale community to continue experiencing the universe created by Toby Fox. These projects are a testament to the passion and creativity of fans who are inspired by the original game’s storytelling, characters, and unique gameplay.
The Role of Fangames in a Franchise
Fangames like Undertale Red and Yellow play a crucial role in keeping a beloved franchise alive and engaging for its fanbase. They offer opportunities for players to:
- Experience new narratives: Explore “what if” scenarios or delve into lore that was only hinted at in the original.
- Discover new gameplay mechanics: Developers often experiment with new combat systems, puzzles, or interaction methods.
- Support fan creativity: By playing and sharing these games, fans encourage and support independent creators within the community.

Community and Development Updates
The development of Undertale fangames is often a collaborative and transparent process. Developers frequently share progress updates, screenshots, and demo versions through community platforms. Engaging with these communities can provide:
- The latest download links: Stay informed about the most recent stable builds.
- Troubleshooting support: Connect with other players and the developers for help with any issues.
- Behind-the-scenes insights: Learn about the creative process and the challenges of developing these ambitious projects.
By following the steps outlined above, you can successfully install and begin playing Undertale Red and Undertale Yellow, expanding your journey through the rich and captivating world of Undertale. These fan-made adventures offer compelling new stories and experiences that are sure to delight any fan of the original game.
