Super Minitroid v2 - Restore Horizontal Momentum

super metroid rom hack ips patch game development on August 5, 2025

Fixed horizontal momentum in Super Minitroid - now with proper air control and wall jump momentum.

Note: The latest version further restores horizontal momentum after wall jumps (which was not restored at the time of the video).

The Problem

Super Minitroid didn't just reduce horizontal momentum - it completely eliminated air control in multiple movement scenarios, making platforming feel unresponsive.

Installation

Method 1: Apply v2 Patch Directly

Apply patch: Use multipatch to apply Super Minitroid v2.ips to Super Minitroid.smc
Result: Super Minitroid v2.smc with restored air control

Method 2: Two-Step Process

Apply base patch: Apply Super Minitroid.ips to Super Metroid (JU) [!].smc
Apply v2 patch: Apply Super Minitroid v2.ips to the resulting ROM

Memory Addresses Fixed

Address	Function	Original	Super Minitroid	Fixed
0x81F71	Non-spinning jump horizontal speed	01	00	✅
0x81F7D	Spinning jump horizontal speed	01	00	✅
0x81F65	Running max speed	02	01	✅
0x81FA1	Horizontal speed after ledge fall	01	00	✅
0x82049	Wall jump horizontal speed	01	00	✅

Result: All movement types now have proper horizontal momentum (0→1+ = infinite improvement)

Files Included

Super Minitroid.ips (206K) - Base Super Minitroid patch
Super Minitroid v2.ips (38B) - Momentum fix patch (5 single-byte modifications)
Super Minitroid v2.smc (4.0M) - Final patched ROM with fixed momentum
create_super_minitroid_v2_ips.py - Script to generate custom patches

Technical Details

IPS Patch Structure

Format: Standard IPS (PATCH...EOF)
Size: 38 bytes (5 single-byte modifications)
Base ROM: Apply to Super Minitroid.smc

Customization

python3 create_super_minitroid_v2_ips.py

Edit line 36 to change speed value, then run to generate a new patch with custom momentum settings.

Note: If values are too high, Samus will clip through tiles.

What's Fixed

The v2 patch restores proper air control by modifying five critical memory addresses that control horizontal momentum in different movement states:

Non-spinning jumps: Restored horizontal control during regular jumps
Spinning jumps: Fixed momentum during spin jumps
Running speed: Increased maximum running speed
Ledge falls: Maintained momentum when falling off platforms
Wall jumps: Restored horizontal momentum after wall jumps (latest improvement)

This makes Super Minitroid feel much more responsive and closer to the original Super Metroid's fluid movement system while maintaining the hack's intended difficulty and design changes.