- Project Reclaimer custom gamemodes combine scripted rules with Halo 3 multiplayer foundations like Slayer.
- Built-in modes include Gun Game, Growth, One in the Chamber, Zone Control, and Flood Infection.
- Megalo scripting drives the logic layer: events, conditions, actions, and variables.
- JSON configuration separates mode settings from gameplay logic for cleaner scripts.
- Servers share content automatically, so players can join custom modes without manual file setup.
What Are Project Reclaimer Custom Gamemodes?
Project Reclaimer custom gamemodes are modified multiplayer rulesets that run on the standalone Halo 3 PC client. Instead of being limited to standard Slayer or CTF, players can join servers running scripted modes with unique objectives, progression systems, and victory conditions. The project supports both ready-to-play scripted game modes and creation tools for building your own, according to the official modes page.
The system is built on three layers that work together:
| Layer | Purpose | Examples |
|---|---|---|
| Base mode | Starting ruleset and teams | Slayer foundation, team setup |
| Script logic | Events, conditions, actions | Kill detection, zone capture, role changes |
| Configuration | Structured mode settings | JSON values, timers, HUD elements |
Most custom modes begin from a Slayer-style base. Add variables, events, and HUD elements one at a time so unexpected behavior stays easy to trace.
Custom gamemodes fit into the broader Project Reclaimer ecosystem alongside the server browser, expanded Forge, dedicated servers, and automatic mod downloads. When a server runs a mode you don't have installed, the client can fetch the required files before you connect, keeping the join flow smooth.
Built-In Scripted Modes Overview
Project Reclaimer ships with several scripted modes that double as reference implementations. Studying how each one handles progression, resources, and round logic is the fastest way to learn the scripting system before writing your own rules.
Gun Game
- Progression mode
- Advance through a weapon sequence
- Weapon assignment per kill event
- Final stage sets victory condition
Growth
- Player-state mode
- Power or status scales over the match
- Persistent player variables
- HUD feedback on current state
One in the Chamber
- Limited-ammunition mode
- Restricted resources per life
- Eliminations restore ammunition
- Round logic ends the match
Zone Control
- Objective mode
- Capture and hold territories
- Contested-state detection
- Zones, timers, and team scoring
Flood Infection
- Infection mode
- Human vs Flood role split
- Infection events convert players
- Round ends on victory condition
Custom Scripts
- Your own rules
- JSON configuration layer
- Megalo logic layer
- Reusable timers, zones, HUD blocks
Here is how the built-in modes compare in terms of scripting complexity and best use cases:
| Mode | Type | Core Systems | Complexity | Best For |
|---|---|---|---|---|
| Gun Game | Progression | Player vars, weapon assignment | Medium | Classic arena servers |
| Growth | Player-state | Persistent vars, status updates | Medium | Casual large lobbies |
| One in the Chamber | Limited-resource | Inventory control, counters | Low-Medium | Small duels |
| Zone Control | Objective | Zones, timers, team scoring | Medium-High | Team play servers |
| Flood Infection | Role-based | Team changes, respawn logic | High | Community events |
Each built-in mode demonstrates a different scripting pattern. Zone Control is the best reference for objective logic, while Flood Infection shows how to handle mid-match team and role changes.
How Custom Mode Scripting Works
Custom gamemode creation in Project Reclaimer combines two layers: Megalo for gameplay logic and JSON for structured configuration. The official project supports a subset of the ReachVariantTool Megalo language, so scripts built around events, conditions, actions, and variables translate directly into match behavior.
The Megalo Logic Layer
Megalo reacts to what happens during a match. A typical rule connects an event (such as a player elimination) to conditions (checks on variables or team state) and actions (changes to scores, loadouts, or respawn behavior). Common building blocks include:
| Building Block | What It Does | Typical Use |
|---|---|---|
| Events | Triggers when something happens | Kill events, round start, timer expiry |
| Conditions | Evaluates game state | Team checks, score thresholds |
| Actions | Changes game state | Award points, swap teams, give weapons |
| Variables | Stores persistent data | Player stats, growth levels, round state |
| Timers | Time-based control | Capture progress, cooldowns, match limits |
| Zones | Area detection | Objective control, contested states |
| HUD elements | Player feedback | Score display, status text, instructions |
The JSON Configuration Layer
JSON describes mode settings, default values, object references, and script data separately from the logic itself. Keeping names and values organized by purpose, and using consistent identifiers for objectives, timers, teams, and HUD elements, makes modes far easier to revise and debug. Validate the structure before loading the mode, and change configuration values separately from logic whenever possible.
Test each rule on its own before combining multiple systems. Layering several untested scripts together makes it much harder to identify which rule caused unexpected behavior.
Step-by-Step: Build Your First Custom Gamemode
Follow this workflow to go from a blank Slayer foundation to a tested custom mode running on a server.
Start from a Slayer foundation
Create a new mode based on the standard Slayer ruleset. This gives you functional teams, scoring, and respawn behavior without writing them from scratch. Confirm the base mode works before adding any custom logic.
Define variables and configuration
Add JSON configuration for the values your mode depends on: progression targets, timers, zone definitions, and HUD labels. Use consistent identifiers so the script layer can reference them cleanly.
Write the core rule logic
In Megalo, connect events to conditions and actions. Start with a single core rule, such as awarding progression on an elimination event, and verify it behaves correctly in a test session.
Add HUD feedback and round logic
Communicate state to players with HUD elements showing score, status, and time remaining. Then implement round-end conditions: target score, timer expiry, or last-player-standing logic depending on your mode type.
Test locally, then on a server
Test the mode solo first to catch obvious errors, then host a session through a dedicated server and invite players. Verify spawning, objectives, boundaries, and performance with a full lobby before publishing.
Before sharing your mode publicly, confirm it loads cleanly, round-end logic fires reliably, and joining players receive the required files automatically through server-side content sharing or Steam Workshop.
Running Custom Gamemodes on Servers
Server operators play a key role in the custom gamemode ecosystem. A dedicated Project Reclaimer server can host persistent sessions with custom maps and modes, and the client handles missing content for joining players. The official hosting guide covers deployment on Windows, Windows Server, and Linux Docker.
Key considerations for mode-focused servers:
| Consideration | Why It Matters | Recommended Practice |
|---|---|---|
| Content directories | Maps and mode scripts must load correctly | Use the expected folder structure, keep references consistent |
| Version compatibility | Client and server must match | Update the server when new releases ship |
| Automatic downloads | Players need mode files to join | Enable server-side content sharing |
| Restart behavior | Config changes need reloads | Restart after adding or changing modes |
| Anti-cheat | Public sessions need protection | Keep protections enabled, maintain a ban list |
Always restart or reload the server after adding a new mode or map, then join once yourself to confirm the content loads and the ruleset behaves as intended before advertising the session.
Creation Checklist and FAQ
Custom Gamemode Milestones:
- Set up Project Reclaimer client with Halo 3 content installed
- Play every built-in scripted mode at least once
- Build a first mode from a Slayer foundation
- Add HUD feedback and reliable round-end logic
- Test the mode with multiple players on a server
The fastest path to mastering custom gamemodes is reverse-engineering the built-in modes. Each one isolates a different scripting pattern, from progression tracking to zone control to role conversion.
Q: Do I need to install custom gamemode files manually before joining a server?
Usually not. Project Reclaimer servers can advertise and share the content their sessions require, so the client can download missing mode files automatically when you join. Steam Workshop support provides another distribution channel for supported content.
Q: What scripting language do Project Reclaimer custom gamemodes use?
Custom mode logic uses Megalo, with the project supporting a subset of the ReachVariantTool Megalo language. JSON handles the structured configuration layer for mode settings, values, and references.
Q: Which built-in mode is best for learning objective-based scripting?
Zone Control is the strongest reference for objective logic. It demonstrates zones, player presence detection, contested states, team scoring, timers, and objective HUD elements working together.
Q: Can I run custom gamemodes on my own server?
Yes. A dedicated Project Reclaimer server can host custom maps and game modes persistently. Place mode content in the expected directories, reference it in the server configuration, and restart the server after changes.