G3M

G3M is a free, open-source desktop manager built specifically for GameMaker mods. It is the strongest fit for players and creators working with supported GameMaker titles who want profiles, patch construction, and flexible installation in one place. Choose it for that focused workflow; look elsewhere if you need a broad, engine-agnostic mod catalogue.

Overview

G3M combines mod discovery, installation, organisation, editing, and game launching in a single application. Its built-in entries cover DELTARUNE, DELTARUNE Demo, UNDERTALE, UNDERTALE Yellow, Pizza Tower, Sugary Spire, and FRICKBEARS3. The in-app Game Manager can add custom GameMaker games, extending the catalogue beyond those entries without changing the software’s specialist focus.

Integration with GameBanana supports browsing for supported games, while installation also accepts GameBanana items, external URLs, local archives, and one-click install links. That mix works well for users who move between a public mod hub and files obtained directly from creators.

Key features

Profiles and conflict handling

Users can create multiple library profiles, each with its own active mod selections and profile-scoped settings. Separate profiles are practical for different playthroughs, testing combinations, or keeping one setup for another household user. Conflict detection identifies overlapping changes, helping users investigate incompatibilities before launch; it does not decide which competing change should win.

Editing and patching

The Mod Editor combines patches, file replacements, and archive contents, then exports the result as a shareable mod. Built-in tools create and apply patches, merge patch sets, compare files, export diff reports, and convert mods between supported formats. This is a meaningful advantage for mod authors and curators who need repeatable file work. Players who only install finished mods may find much of this capability unnecessary.

Launching, plugins, and presentation

Games can launch directly or through Steam where available. On Linux, PortProton can be used for compatible Windows games. Normal launch mode restores game files after the game closes, a useful safeguard when mods alter originals. The Catalog adds plugins and themes, including DR Save Manager for DELTARUNE saves and Custom Saves Folders for choosing save locations. Installed or imported themes and language packs for English, Russian, Spanish, Korean, Japanese, Simplified Chinese, and Traditional Chinese make the interface adaptable.

Pricing

G3M — free. This is a GPL-3.0 desktop application with no free trial because the software is free and open source. There are no paid tiers, seat counts, renewal terms, or usage quotas to weigh. The trade-off is scope rather than price: value depends on whether your games fit the GameMaker-focused workflow.

Platforms

G3M runs on Linux, macOS, and Windows. Release downloads target x86_64 and ARM64 computers. Supported games can use Steam launching where available, and Linux users have the additional PortProton route for compatible Windows titles.

Who it's for

G3M suits GameMaker players who manage several mod combinations, creators who build or convert patches, and households that need separate profiles. It is also a sensible choice for users who obtain mods through more than one channel or want save-management plugins. It is less appropriate as a general manager for games built on unrelated engines, or for someone seeking a universal catalogue rather than a focused GameMaker tool.

Pros and cons

• Pros: Profiles isolate active selections and settings, making alternate setups safer to maintain.
• Pros: Patch creation, merging, comparison, diff reports, and format conversion support genuine mod-authoring work.
• Pros: GameBanana, URLs, archives, and one-click links cover varied installation sources.
• Pros: Windows, Linux, and macOS releases include both x86_64 and ARM64 builds.
• Cons: The built-in game catalogue is concentrated on a small set of GameMaker titles.
• Cons: Advanced editing tools add little for users who only install ready-made mods.
• Cons: Security fixes are best-effort for the main branch and latest release; older releases are unsupported.

Alternatives

Browse Game Mod Managers for a wider comparison. Choose Mod Organizer 2 instead if you need a free, open-source Windows manager for Windows 10 1809 or Windows 11, noting that Windows Store and Game Pass versions are unsupported. Limo is a free, open-source Linux alternative. Modrinth is better when a freemium, multi-platform service with web access and creator-support features suits you. CurseForge is a web-based choice for Minecraft mods and modpacks. Vortex offers a free, open-source Windows manager tied to Nexus Mods. Modrix is a free, open-source option spanning browser extension, Linux, macOS, and Windows. FlairX Mod Manager is a free Windows-only alternative. HFW Mod Manager targets supported Decima-engine games on Linux and Windows.

Verdict

G3M is a strong recommendation for GameMaker mod users who want profile separation and creator-grade patching alongside discovery and launching. Its free GPL-3.0 model removes licensing friction, and its cross-platform builds broaden access. Look elsewhere when your library is mostly non-GameMaker games, when you want a broad general-purpose ecosystem, or when maintaining an unsupported older release would be a concern.