1-Bit Fantasy: A public domain JRPG prototype

brett · April 29, 2026, 2:26pm

I set out on a little quest: could I make a game like Final Fantasy Legend or Dragon Quest in 2 weeks?

Two weeks later, here's what I've got: 1-Bit Fantasy:

1-Bit Fantasy Combat

It's a prototype made with Lua. After I finished the first draft of my Playdate book, I wanted to expand upon the final project to make a bigger turn-based RPG. And then share the source for those who might want to make their own JRPG.

You can download 1-Bit Fantasy on itch:

And download the source on GitHub (it's all public domain):

1-Bit Fantasy features:

Map exploration with 3 different maps; using Tiled
NPC conversations
Turn-based combat
Save and load data
Sound effects and music

Basically, a lot of the foundations you'd need to make your own JRPG for Playdate.

Technical Aspects

I tried to write the Lua code in such a way that's all data-driven and without too many globals. Here are some interesting bits:

OptionSelect has a draw and update function that can be used to easily add menus, since there are so many in the game:

github.com/brettchalupa/1_bit_fantasy

source/ui.lua

28d1ead12


      
          -- Handles input for a table of options, calling the `onSelect` callback on the
          -- current option.
          -- Returns the updated `index`, which the caller must use to update the index.
          local function updateOptionSelect(index, numOptions, onSelect)
            if playdate.buttonJustPressed(playdate.kButtonUp) then
              PlaySFX(SFX.MENU_UP)
          
              index -= 1
          
              if index < 1 then
                index = numOptions
              end
            end
          
            if playdate.buttonJustPressed(playdate.kButtonDown) then
              PlaySFX(SFX.MENU_DOWN)
          
              index += 1
          
              if index > numOptions then

This file has been truncated. show original

It's used throughout combat, menus, and NPC dialog trees.

And then MessageQueue.push and MessageQueue.pop power all of the combat and NPC textboxes:

github.com/brettchalupa/1_bit_fantasy

source/message_queue.lua

28d1ead12


      
          local queue = {}
          
          MessageQueue = {
            -- `msg` specification: a table that can contain:
            -- - `text` - the text to display
            -- - `speaker` - (optional) who is speaking
            -- - `onShow` - (optional) callback function called when first shown
            -- - `onConfirm` - (optional) callback function called when A button is pressed to advance to next msg
            push = function(msg)
              table.insert(queue, msg)
            end,
          
            pop = function()
              return table.remove(queue, 1)
            end,
          
            clear = function()
              queue = {}
            end
          }

From anywhere in the game, messages can be pushed onto the queue:

MessageQueue.push({
  speaker = "Innkeeper",
  text = "Welcome to the Generic Village Inn! The finest (and only) inn in the village.",
})

Messages have optional onShow and onConfirm callbacks, which can push more messages on the queue or change game state.

Which all gets rendered by MessageBox:

github.com/brettchalupa/1_bit_fantasy

source/message_box.lua

main

local gfx <const> = playdate.graphics

local MSG_BOX_HEIGHT = 64
local MSG_BOX_MARGIN = 8
local MSG_BOX_PADDING = 8
local SPEAKER_BOX_HEIGHT = 32
local PROMPT_RADIUS = 12
local CHOICE_SPACING = 26
local CHOICE_BOX_WIDTH = 80

local activeMessage = nil
local elapsed = 0
local selectedChoice = 1

local function hasChoices()
  return activeMessage and activeMessage.choices and #activeMessage.choices > 0
end

local function tryNextMessage()
  activeMessage = MessageQueue.pop()

This file has been truncated. show original

The MessageBox handles rendering and updating the message on the top of the queue, if there is one.

Lastly, I think the code for handling scenes and subscenes is pretty elegant:

A scene is a table that has an update function and optional init and close functions:

github.com/brettchalupa/1_bit_fantasy

source/scenes/gameplay.lua

28d1ead12


      
          local scene = {
            update = update,
            init = init,
            close = close,
          }

main.lua calls out to the current scene and handles switching:

github.com/brettchalupa/1_bit_fantasy

source/main.lua

28d1ead12


      
          if pendingScene then
            currentScene = pendingScene
            if currentScene.init then
              currentScene.init()
            end
            pendingScene = nil
          end
          
          currentScene.update(dt)

And the Gameplay scene has subscenes (field, combat, and menu)

github.com/brettchalupa/1_bit_fantasy

source/scenes/gameplay.lua

28d1ead12


      
          local subscenes = {
            [FIELD_SUBSCENE.FIELD] = import("scenes/gameplay_subscenes/field"),
            [FIELD_SUBSCENE.COMBAT] = import("scenes/gameplay_subscenes/combat"),
            [FIELD_SUBSCENE.MENU] = import("scenes/gameplay_subscenes/menu"),
          }

Lua isn't the language I'm most comfortable with, so some of this may be a bit weird, but I really love how flexible Lua is. Structuring the game into scenes and subscenes and being easily able to switch between them made developing pretty quick.

Sunny

Right before I started 1-Bit Dungeon, I made a Playdate Lua template that has some of these foundations called Sunny :

It has the scene switching and some organization of the code. I'll backport some of the stuff from 1-Bit Dungeon to Sunny soon.

What I Didn't Get To

I planned to add magic spells, items, and equipment, but I wasn't able to get those done. I do think they're similar enough systems to what exists that it wouldn't be a big leap to add them. They'd be great to add in a full game.

Asset Credits

Monster Sprites:
Hexany's Monster Menagerie
(CC0)
Map Sprites: Kenney's 1-Bit Pack (CC0)
Music tracks: [BitMidi](https://bitmidi.com/

What Next

Well, that's the big question! I am going to finish editing the Playdate book. Then make some smaller prototypes before I decide what kind of bigger project I want to commit to. I have an idea for a multi-hour JRPG that'd be a good fit for Playdate. But that'd be a big commitment that I'm not sure I'm quite ready for.

Hope you enjoy the prototype and let's all make some great RPGs for Playdate!

brett · May 5, 2026, 11:50am

I made a video playing through the game and then walking through some of the more interesting bits of the source code to help people jump in and make it their own!