Extending the demo: Swagman

Demo versions of Swagman with more than the expected amount of swag

Mar 28, 2024

In this edition:

There a couple of demo discs that feature pre-final versions of Core Design’s Swagman.
The demos restrict you to the first section of the game, but they have data for lots more.
By working around the demo limits, we can explore more of these prototype builds.

There are patches available at SegaXtreme! Here’s a video of some gameplay:

Intro

When we last looked at the Core Demo Disc, we found that it had a surprise: the “rolling demo” of Fighting Force can be made playable. But what about the other demos? Is there any more to them?

For Swagman, the answer is yes: Core Demo Disc contains a more-or-less full build of the game. Furthermore, it’s a prototype build: its files are from 1997-03-14, approximately 3 months before the final game’s.

On top of that, there’s another demo disc with a similar secret: Swagman Playable Demo is based on an even earlier prototype, and it’s got a full game build too. It’s files are dated 1997-02-10, which makes it older than the 1997-02-26 prototype.

Below are details about how to explore these builds, notes on the places where you’ll get stuck when playing, and some observations on how these builds differ from the final game.

Technical details: going downstairs

The first thing we need to do is lift the demo restrictions. You can normally play in the upstairs part of Zack’s house, and the demo ends before you go downstairs.

The earlier demo states that the full game will be available in March of 1997. The later one (from March of 1997), is silent on the matter.

“Save and load game feature?” Sign me up!

Swagman is kind of a Metroidvania - you’re constantly running back and forth between stages to unlock previously-inaccessible areas. These memory addresses store your location:

Standalone disc (2 bytes each)
* Stage: 060cdff6
* Room: 060dfe00 

Core disc (4 bytes each)
* Stage: 060cae40
* Room: 060de17c

Both demos have a function that detects when you leave stage 01. This triggers the end-of-demo screen. We can nullify jumps away from the gameplay with these patches:

# Standalone disc:
060122ca 0009
060122ce 0009

# Core disc
060109d8 0009
060109dc 0009

This gets us downstairs, and allows us to explore more of the builds.

Where you’ll get stuck

We can play the standalone demo for a while before we encounter a major obstacle. One room downstairs has a floor that’s supposed to break after you walk on it. But when you get to it, it’s already broken. This is fixed in the 1997-02-26 build, and in the Core demo.

Left: The standalone demo. Right: The Core demo.

I played around with different methods for getting past this, but the easiest is to adjust Zack’s jump height:

# Standalone disc
0603142c 0601 8000

# Core disc
060491a0 0601 8000

I also needed a higher jump for the garden. You’re meant to bounce on the spider web and land on the platform across the chasm. But I couldn’t make it without some hacking in either build:

The standalone demo starts running out of steam in the garden area. It should transport you to the Limbo stage when you get to this spot, but it doesn’t:

You can keep playing for a while if you’re persistent, but you’ll be stuck once you get to the basement: it doesn’t load.

The Core demo lets you keep going for a while longer: you can do the Limbo stage and fight the pumpkin boss. But you’ll be stuck once you get to the basement and need to free Hannah. You can teleport her to where she needs to be, but when you try to switch to her the game crashes (interestingly, this also happens in the auto demo):

Core Demo Disc: Note the unfinished graphics on the left. You can’t get Hannah off the teleport pad without more hacking.

You need her to finish the basement, so this is the end of the line. You can switch characters manually by editing these memory addresses if you want to keep going, but don’t hit X or Z:

# Core disc
060d4fb0 0000 00001

Also, if you’re just exploring, you can make yourself invincible with these memory patches:

# Standalone disc
06032200 0009

# Core disc
0604a0b6 0009

Prototype differences

You’ll notice lots of differences between these demo builds and the final game even without hacking. For example, the title screens on the demos are similar, but neither looks like the final version:

Left: the standalone demo. Right: the final game.

The loading screens got reworked over time. The standalone demo has a picture of a house with a text description (this matches the 1997-02-26 prototype). The Core demo has the picture of the house, but no text. The final version has artistic depictions of the characters:

Left: the Core demo. Right: the final game.

With some hacking, we can access the Options menu. The demo builds have different items from the final game:

Left: The demos’ options screen. Right: the final game’s options screen.

Interestingly, the demos say AZ to change and Q to select. Was there supposed to be a PC port?

There seem to be lots of other minor differences in enemy and item placement, and overall polish in the different builds. If you spot something cool, point it out to me!

One more cool thing: you can control the auto demos. This lets you play as Hannah in the standalone demo. Once they begin, edit these memory locations to take control:

# Standalone disc
060c0f18 01

# Core disc
060c2c38 01

Outro

As usual, you’re welcome to use the screenshots and information here on your favorite reference site (Hidden Palace, TCRF, Sega Retro, etc.). For previous coverage of demo discs with extra prototype content on them, see:

You can send me suggestions for things to look into! Thanks to Cerbero for encouraging me to check into these Core Designs demo discs.

Rings of Saturn