Easy Mode Mod Configuration Guide

Introduction

Easy Mode Mod is a mod for The Binding of Isaac: Repentance that reduces game difficulty by slowing down enemy attributes.

Configuration Files

File	Description
`config.lua`	User configuration file (managed separately, no git conflicts)
`config.lua.example`	Default configuration template
`CONFIG.md`	Chinese documentation
`CONFIG.en.md`	This English documentation

Quick Start

1. Modify Configuration

Edit the config.lua file. Use a text editor like VS Code or Notepad++:

return {
    ENEMY_SPEED_FACTOR = 0.4,              -- Enemy move speed (0.4 = 60% reduction)
    BOSS_SPEED_FACTOR = 0.7,               -- Boss move speed (0.7 = 30% reduction)
    PROJECTILE_SPEED_FACTOR = 0.95,        -- Projectile speed (~5% reduction, ~19% range reduction)
    TEAR_SPEED_FACTOR = 0.95,              -- Tear speed (same as projectile)
    ROCK_WAVE_SPEED_FACTOR = 0.9,          -- Rock/Wave speed (~10% reduction, ~19% range reduction)
    BOMB_EXPLOSION_DELAY_MULTIPLIER = 1.5, -- Bomb explosion delay (1.5x)
    ATTACK_COOLDOWN_MULTIPLIER = 1.5,      -- Attack cooldown multiplier
    EXCLUDE_FRIENDLY = true,               -- Exclude friendly units
    EXCLUDE_FAMILIARS = true,              -- Exclude familiars
    ENABLE_ATTACK_SLOWDOWN = false         -- Enable attack slowdown (experimental)
}

2. Restart Game

After modifying config.lua, you need to completely restart the game (not just reload the mod).

Physics: Range and Speed

Parabolic Motion and Range

Projectiles follow a parabolic trajectory. The range formula is:

R = (v² × sin(2θ)) / g

Key Discovery: Range is proportional to the square of velocity!

Speed Factor	Actual Speed	Expected Range	Range Reduction
1.0	100%	100%	No reduction
0.98	98%	96%	-4%
0.95	95%	90%	-10%
0.9	90%	81%	-19%
0.85	85%	72%	-28%
0.8	80%	64%	-36%

Examples:

Speed factor 0.95 → 5% speed reduction, but ~10% range reduction
Speed factor 0.9 → 10% speed reduction, but ~19% range reduction

Configuration Suggestions

Adjust based on desired difficulty:

Difficulty	PROJECTILE/TEAR_SPEED	ROCK_WAVE_SPEED	Range Reduction
Light	0.98	0.95	~4-10%
Medium	0.95	0.9	~10-19%
Heavy	0.9	0.85	~19-28%

Configuration Parameters

Speed Control Parameters

ENEMY_SPEED_FACTOR

Default: 0.4
Description: Movement speed factor for regular enemies (Type 10-999)
Effect: Enemy movement speed reduced by 60%

BOSS_SPEED_FACTOR

Default: 0.7
Description: Movement speed factor for Bosses
Effect: Boss movement speed reduced by 30%
Note: Some bosses may not slow down due to game mechanics

PROJECTILE_SPEED_FACTOR

Default: 0.95
Description: Speed factor for enemy projectiles (Type 9, Spawner >= 10)
Effect: ~5% speed reduction, ~10% range reduction
Physics: Range proportional to speed squared

TEAR_SPEED_FACTOR

Default: 0.95
Description: Speed factor for enemy tears (Type 2, Spawner != Player)
Effect: Same as projectile
Note: Enemy tears are actually Type 9 (ENTITY_PROJECTILE), distinguished by SpawnerType

ROCK_WAVE_SPEED_FACTOR

Default: 0.9
Description: Speed factor for special projectiles (Stone Waves, Rocks, etc.)
Effect: ~10% speed reduction, ~19% range reduction
Detection: Only affects ProjectileVariant.PROJECTILE_ROCK

Time Control Parameters

BOMB_EXPLOSION_DELAY_MULTIPLIER

Default: 1.5
Description: Bomb explosion delay multiplier
Effect: Bomb explosion time extended by 50%
Implementation: Uses EntityBomb:SetExplosionCountdown()

ATTACK_COOLDOWN_MULTIPLIER

Default: 1.5
Description: Enemy attack cooldown multiplier
Effect: Enemy attack interval extended by 50% (experimental)

Exclusion Parameters

EXCLUDE_FRIENDLY

Default: true
Description: Whether to exclude friendly units (charmed enemies)
Effect: Charmed enemies won't be slowed

EXCLUDE_FAMILIARS

Default: true
Description: Whether to exclude familiars
Effect: Player's familiars won't be affected

ENABLE_ATTACK_SLOWDOWN

Default: false
Description: Whether to enable attack slowdown (experimental)
Note: This feature may be unstable

Git Conflict Protection

config.lua uses Git's skip-worktree feature to protect your local changes from git merge conflicts.

Benefits

✅ Your local configuration won't be overwritten when pulling updates
✅ You can modify settings anytime without affecting other users
✅ Perfect for personalized settings

Committing Configuration Changes

If you want to commit your configuration changes:

# 1. Temporarily disable skip-worktree protection
git update-index --no-skip-worktree config.lua

# 2. Commit changes
git add config.lua
git commit -m "Update config with my settings"

# 3. Re-enable protection
git update-index --skip-worktree config.lua

Resetting to Default Configuration

To reset to default configuration:

# 1. Temporarily disable protection
git update-index --no-skip-worktree config.lua

# 2. Reset from template
cp config.lua.example config.lua

# 3. Commit reset (optional)
git add config.lua
git commit -m "Reset config to defaults"

# 4. Re-enable protection
git update-index --skip-worktree config.lua

Preset Configurations

Light Difficulty Reduction (Recommended for Beginners)

return {
    ENEMY_SPEED_FACTOR = 0.5,
    BOSS_SPEED_FACTOR = 0.8,
    PROJECTILE_SPEED_FACTOR = 0.98,
    TEAR_SPEED_FACTOR = 0.98,
    ROCK_WAVE_SPEED_FACTOR = 0.95,
    BOMB_EXPLOSION_DELAY_MULTIPLIER = 1.2,
    ATTACK_COOLDOWN_MULTIPLIER = 1.2,
    EXCLUDE_FRIENDLY = true,
    EXCLUDE_FAMILIARS = true,
    ENABLE_ATTACK_SLOWDOWN = false
}

Medium Difficulty Reduction (Recommended for Most Players)

return {
    ENEMY_SPEED_FACTOR = 0.4,
    BOSS_SPEED_FACTOR = 0.7,
    PROJECTILE_SPEED_FACTOR = 0.95,
    TEAR_SPEED_FACTOR = 0.95,
    ROCK_WAVE_SPEED_FACTOR = 0.9,
    BOMB_EXPLOSION_DELAY_MULTIPLIER = 1.5,
    ATTACK_COOLDOWN_MULTIPLIER = 1.5,
    EXCLUDE_FRIENDLY = true,
    EXCLUDE_FAMILIARS = true,
    ENABLE_ATTACK_SLOWDOWN = false
}

Heavy Difficulty Reduction (Challenge Mode)

return {
    ENEMY_SPEED_FACTOR = 0.3,
    BOSS_SPEED_FACTOR = 0.6,
    PROJECTILE_SPEED_FACTOR = 0.9,
    TEAR_SPEED_FACTOR = 0.9,
    ROCK_WAVE_SPEED_FACTOR = 0.85,
    BOMB_EXPLOSION_DELAY_MULTIPLIER = 2.0,
    ATTACK_COOLDOWN_MULTIPLIER = 2.0,
    EXCLUDE_FRIENDLY = true,
    EXCLUDE_FAMILIARS = true,
    ENABLE_ATTACK_SLOWDOWN = false
}

Supported Entity Types

Entity Type	EntityType Value	SpawnerType	Processing
Regular Enemy	10-999	-	Uses ENEMY_SPEED_FACTOR
Boss	Special	-	Uses BOSS_SPEED_FACTOR
Enemy Projectile	9	>= 10	Uses PROJECTILE_SPEED_FACTOR
Enemy Tear	2	>= 10	Uses TEAR_SPEED_FACTOR
Player Tear	2	1	Not processed
Rock Projectile	9 (Variant=1)	-	Uses ROCK_WAVE_SPEED_FACTOR
Bomb	4	-	Uses BOMB_EXPLOSION_DELAY_MULTIPLIER

FAQ

Q: What do I need to do after modifying the config?

A: You need to completely restart the game, not just reload the mod.

Q: Why is projectile range reduced more than expected?

A: Range is proportional to the square of speed. If speed factor is 0.9, range will be 0.81 (19% reduction).

Q: Can I completely disable projectile slowdown?

A: Yes, set PROJECTILE_SPEED_FACTOR and TEAR_SPEED_FACTOR to 1.0.

Q: Why isn't the Boss slowing down?

A: Some bosses have special movement logic that may not be affected by speed factors. This is a game mechanic limitation.

Q: Configuration not working?

Make sure to completely restart the game
Check config.lua syntax (use an online Lua syntax checker)
Check if other mods are overriding your settings

Technical Details

How It Works

The mod scans all entities in the room every frame using the MC_POST_UPDATE callback:

Get all entities in room: Isaac.GetRoomEntities()
Detect entity type and apply appropriate slowdown
Use weak tables to cache processed entities and avoid duplicate processing

Performance Optimization

Each projectile is only processed once (tracked using processedProjectiles)
Stationary entities are ignored (speed < 0.5)
Entity type filtering for quick processing

Related Files

main.lua - Mod main logic
config.lua - User configuration
config.lua.example - Configuration template
README.md - Mod readme
CONFIG.md - Chinese configuration documentation
CONFIG.en.md - This English documentation

Advanced玩法: Challenge Yourself 🎮

Want Higher Difficulty? No Problem!

This mod supports setting parameters greater than 1.0 to achieve "Hard Mode" or even "Masochist Mode"!

return {
    ENEMY_SPEED_FACTOR = 1.5,              -- Enemies run faster than you!
    BOSS_SPEED_FACTOR = 2.0,               -- Boss moves at 2x normal speed!
    PROJECTILE_SPEED_FACTOR = 1.5,        -- Projectiles fly like bullets!
    BOMB_EXPLOSION_DELAY_MULTIPLIER = 0.5, -- Bombs explode faster!
}

Effect Preview

Parameter	Normal Value	Masochist Value	Effect
ENEMY_SPEED_FACTOR	0.4	1.5	Enemy speed increased by 275%
BOSS_SPEED_FACTOR	0.7	2.0	Boss speed increased by 186%
PROJECTILE_SPEED_FACTOR	0.95	1.5	Projectile speed increased by 58%, range increased by 125%

⚠️ Friendly Reminder

This is not a warning, it's advice from the developer:

Setting ENEMY_SPEED_FACTOR > 1 means enemies might run faster than you

PROJECTILE_SPEED_FACTOR > 1 makes projectiles fly farther and faster

You might need better dodge skills and faster reflexes

We don't guarantee you'll survive Chapter 1

Developer is not responsible for broken controllers, smashed keyboards, or wet monitors

Achievement Unlocked

If you manage to complete the game with this config, please contact the developer:

ENEMY_SPEED_FACTOR = 3.0
BOSS_SPEED_FACTOR = 5.0
PROJECTILE_SPEED_FACTOR = 2.0
ATTACK_COOLDOWN_MULTIPLIER = 0.1  -- Shorter cooldown = More frequent attacks

Good luck! Don't forget to buy extra tissues for your tears. 🧻

License

MIT License (MIT)
Copyright © 2026 Easy Mode Mod Contributors

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.

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