Master Key Pocket - a text-less adventure

Master Key is a Zelda-like with a great focus on exploration and non-verbal dialogue. This is a demake (or a spin-off?) of said game with different elements to create a unique experience for playdate users.

How I discovered this game and why I decided to make a demake of it

Earlier this year, I made a demake of Tunic for the Game Boy Color with GB Studio and a huge inspiration from early Zelda games (especially Link's Awakening). This is the first time I ever made a game publicly available and although it wasn't as popular as other demakes made with GB Studio, it was well received by many who tried it, especially by the Tunic community as it served as an example of what it might look like.

I was flattered by the reception and decided to look further for any mentions. I ended up finding a comment on Reddit about a very similar game but with a greater focus on exploring called Master Key. I liked it, so I searched for more information and managed to find a Discord server where I could talk to the developer. The server is very small but the people are nice and the developer was happy to let me make a demake of Master Key. The suggested platform was the playdate since it was very requested.

Originally, I wanted to remake the game with the playdate's SDK but since it isn't currently compatible with arm-based Chromebooks, I decided to stick with pulp. At first, I didn't like the resolution and limited movement but later on, it made it easier to work anywhere, whenever I wanted.

What has been remade so far

  • Most of the essential tile sets have been faithfully downscaled thanks to the support of the dev.

Downscaled, need some polishing


  • HUD Most of the HUD elements work, except the life gauge (which is based on this thread).
    It's only limited to 4 full halves. Perhaps I could add 2 more variables that represent the second line. but then again it will continue drawing on the first line.

  • Look at it go!|120x80, %
    Basic Movement Animation


It only has been a month and a half since I started working on this, so there's not much to show as I'm still learning how to use pulp. There are still some things that need to be added, so I'll be more active in #pulp if I get stuck on something. This is the first time I have written a development log during development since I typically write one after finishing. I'll be making some updates by the end of every month but I can't guarantee that they will be as long as this one unless I would explain a certain feature.


This is looking really cool, the downscaled art looks great! Accurate but gets across clearly the "demake" vibe.

Thanks, that's the idea, but I'm trying not to make it feel like a worse version of something that already exists.

Never heard of Master Key before but I am ALWAYS down for a Zelda-like!

Update #1
It's been a while since I haven't posted anything here (apart from the Playdate Squad discord server). I've been working on a few major features like a combat system and health system (I'll explain how it works later). I'm almost done with the fundamentals to move on with the game's world. For now, I plan on recreating the demo as closely as possible and mixing things up with some new areas, items, and characters. The title of this demake may now be called Master Key Pocket to differ from the original game.

What has been made so far

  • Combat System & Enemy AI

Enemy Test Room
It's far from perfect, enemies can't handle more than one hit and they can only move in "black" tiles. I previously tested with a script that allows movement on any tile but it doesn't work with multiple enemies, so I'll save it for special enemies that only appear in one screen. As for the fox protagonist, needs to have a knockback and a hurt animation when being hit.

  • Coins

collect 'em all

There are 3 types of coins with greater value than the last. These can be collected and gain health until it reaches your maximum and it even changes the icon, just like in the original.

  • Non-verbal dialogue

sample text
This will be more focused once I start working on the game world. It's going to be challenging to see how many expressions I can make with no text whatsoever and with pictograms that are as small as 8x8.

  • Improved life gauge

Heart Test Room

The Life gauge can finally draw another line of hearts when the previous one is full. It's basically 4 different life gauges that sync with each other.

Here's how it works

First, it converts all empty heart halves to fill empty hearts, in addition to drawing all empty heart rows.

MaxHearts = HalfMax
	MaxHearts /= 2
	HPEmpty = ""
	HPEmpty2 = ""
	HPEmpty3 = ""
	HPEmpty4 = ""

Then, it determines how many hearts need to draw on each line. If the last line reaches its maximum amount of hearts (in this case 4), then the last line only draws its max and the next line adds the current value of MaxHearts and subtracts the amount of the last one. This number multiplies as many rows are added.

HP1Max = MaxHearts
    if MaxHearts>=5 then
		HP1Max = 4
		HP2Max = MaxHearts
		HP2Max -= 4
	if MaxHearts>=9 then
		HP2Max = 4
		HP3Max = MaxHearts
		HP3Max -= 8
	if MaxHearts>=13 then
		HP3Max = 4
		HP4Max = MaxHearts
		HP4Max -= 12

it then draws the given amount of hearts to every line. The way loops work in Pulp is that while x is greater than 0, do y and substracts x and repeat until is no longer greater than 0.

	while HP1Max>0 do
		HPEmpty = "{HPEmpty}{embed:lifeempty}"
	while HP2Max>0 do
		HPEmpty2 = "{HPEmpty2}{embed:lifeempty}"
	while HP3Max>0 do
		HPEmpty3 = "{HPEmpty3}{embed:lifeempty}"
	while HP4Max>0 do
		HPEmpty4 = "{HPEmpty4}{embed:lifeempty}"

then, it does the same thing with the actual hearts as we did with the empty ones.

    HP = HeartHalf
	LifeString = ""
	LifeString2 = ""
	LifeString3 = ""
	LifeString4 = ""
	HP /= 2

It needs to find a way to know when the heart is in half or not. This is where a variable I dubbed as MasterHalf comes in. For some reason, when the HP reaches 3.5 or 4.5 the first line draws more than it should hence when HP reaches those values it does the same thing as it reaches 3

    HP1 = HP
	MasterHalf = HP
	MasterHalf = floor HP
	MasterHalf -= HP
	if MasterHalf!=0 then
		if HP<=3 then
			//Bugfix starts here
		elseif HP<=3.5 then
		elseif HP<=4.5 then
			//Bugfix ends here
		elseif HP<=7 then
		elseif HP<=11 then
		elseif HP<=16 then

repeat the same thing as we did with empty hearts but with full hearts.

	if HP>=4 then
		HP1 = 4
		HP2 = HP
		HP2 -= 4
	if HP>=8 then
		HP2 = 4
		HP3 = HP
		HP3 -= 8
	if HP>=12 then
		HP3 = 4
		HP4 = HP
		HP4 -= 12
while HP1>0 do
		LifeString = "{LifeString}{embed:lifefull}"
	while HP2>0 do
		LifeString2 = "{LifeString2}{embed:lifefull}"
	while HP3>0 do
		LifeString3 = "{LifeString3}{embed:lifefull}"
	while HP4>0 do
		LifeString4 = "{LifeString4}{embed:lifefull}"

And finally, it draws the heart halves if there are any.

if MasterHalf!=0 then
		if HP<=3 then
			LifeString = "{LifeString}{embed:lifehalf}"
		elseif HP<=7 then
			LifeString2 = "{LifeString2}{embed:lifehalf}"
		elseif HP<=11 then
			LifeString3 = "{LifeString3}{embed:lifehalf}"
		elseif HP<=16 then
			LifeString4 = "{LifeString4}{embed:lifehalf}"

Here's the draw function

// Draw Empty Hearts
	if HPEmpty!="" then
		label "{HPEmpty}" at 20,1
	if HPEmpty2!="" then
		label "{HPEmpty2}" at 20,2
	if HPEmpty3!="" then
		label "{HPEmpty3}" at 20,3
	if HPEmpty4!="" then
		label "{HPEmpty4}" at 20,4
// Draw Full (or half) hearts
	if LifeString!="" then
		label "{LifeString}" at 20,1
	if LifeString2!="" then
		label "{LifeString2}" at 20,2
	if LifeString3!="" then
		label "{LifeString3}" at 20,3
	if LifeString4!="" then
		label "{LifeString4}" at 20,4

Update #2
Unfortunately, I wasn't able to work on this project as much as I wanted to. This month's plan was originally focused on improving the game's combat system but I drifted away from that and ended up making the inventory screen (or subscreen). Unlike some of the major additions, the inventory screen is nearly complete, and is very different from the original since it uses the crank. Here's a small side-by-side comparison (all of the icons are placeholders excepy the key).

Original (may look outdated)


Some things had to be cut to have space like the hud and the whole selection screen had to be reinvented to take advantage of the crank but looks good enough to me. The crank concept is inspired by The Legend of Zelda: Twilight Princess for the Gamecube where you use the C-Stick to select the item from a wheel and use the face buttons. I decided to use the D-pad to do other actions like manually saving the game (if autosaving isn't trustworthy), opening a fullscreen map, exiting the game, and other options by double-taping on the D-pad; these don't work at the moment. Here's the crank wheel in action.

I also made some other small additions like the GIF below but the inventory screen is the bigger showcase as this is a concept I had since I started thinking about how Master Key would work on the playdate. I've been busy these past few weeks and I can't promise that I'll be able to post an update for the next month.

Also, Happy Halloween to those who celebrate it as we don't celebrate it here.


Update #3

As I mentioned in my previous update, I couldn't guarantee that I'd make another major update. Still, I improved the existing combat system (especially by adding player knockback).

Shared enemy health
two of them
Pulp doesn't use local variables to make every tile have its variable. To solve this, all common enemies share the same health points but it resets when one is killed. For example, if you hit one enemy and then another, it will die quicker, but the rest will be slightly stronger.

Player knockback
This took longer than it needed to, as it took a lot of trial and error to get this to work with still and moving tiles. It uses the player's current position and the position of where it was attacked to check if the tiles behind are not solid (to prevent any exploits) and moves the player to the non-solid location. @ncarson9 helped with playtesting this on real hardware (which I must admit looks gorgeous) and providing feedback.

And that's pretty much this update. I have big plans for the next couple of months but I won't spoil it all.

1 Like

Update #4

A new year, a new update

Last month was a big update and probably the biggest one yet. This time, I'll list them with hidden text. I want to try to do something different for this year, so let me know if you prefer to have it listed this way.

Added a title screen & logo

Current Title Screen

Master Key's logo is symmetrical which, it wasn't too difficult to recreate it with the new subtitle. The logo you have seen in the gif above is downscaled by hand to meet Pulp's half-resolution. In the title screen, some hidden tiles handle the interaction of the buttons for the "play" and "settings" buttons and even the "load screen." The settings menu is simple and uses menu, so it can work with the inventory screen. I wish that 'menu' could work horizontally and could skip lines.

Added lightning

"Let there be light"

This was something I wanted to add since I made my first post. It's copypasted from this. It essentially changes the tile frame nearby from 0 to 1 in a dark room. I made a new set of tiles with only a single frame, so they're always bright. The only thing left is to make sprites bright near another light source.

Added swimming


Previously, the player could only walk in shallow water, but now it can swim in deep water (and I plan to make it able to dive). The ability to swim and dive will be separate items, and the player cannot attack while swimming, making it vulnerable to projectiles.

Improved combat

After three months of improving this, I can safely say it's finished. Every time you hit a sprite, it calls a function instead of having a list of conditions for every sprite in every weapon, and so does the player. It can now die and respawn. It even saves when you do.

Added snow

screenshot (5)

This is just a detail and shouldn't be considered a feature, but it's winter, and I find this kind of fun. You can reset the path by opening and closing the inventory or moving to the next room.

Animations for trailers

I want to make the trailers have something more to show than just gameplay, and the same person who made the cover art for the Tunic demake is willing to make very short animations for the trailer. Here's one of the illustrations used for the storyboard of one of those animations with only promotional art of the original game as a reference.



Update #5

It's been a couple of months since my last update. I went back to the drawing board and I'm focusing more on adding new content instead of adding it when the player discovers it for the first time. I made sure these fit in the game's context.

About the reveal trailer

For those who don't know, I made a trailer for the 2023 Playdate Community Awards. I didn't see it live as I didn't know it would play so early. This is the first time I ever made a trailer. I'll admit, it wasn't the greatest comparing it to other trailers shown because it was rushed. I had to remove the intro because of the song of choice (which was a sample song that was converted with xm2pulp), made some scenes from the original game and some made just for the trailer. Also, the animations I promised in my previous post couldn't make it because he broke his drawing tablet and lost everything regarding the animation. Nevertheless, It's not bad for my first time and there's room for improvement.

Added a new "Key" mechanic

This will be one of the core mechanics, you insert the key and lock (no pun intended) the player's position and buttons to allow use of the crank for almost anything that requires it. This will be useful to open shortcuts or doors. I think this gives the key a better role than just a weapon comparing it to the original game and gives a whole new meaning to the word "Master Key"

Added three new weapons

These are similar code-wise as they use projectiles but they should be balanced. I think these are familiar enough to need a GIF.

Asset1ㅤㅤㅤㅤBow and Arrow

A simple bow and arrow that depletes your money every time you use it. I could easily create an inventory for arrows but knowing how easy it is to collect coins, it adds another use to them.


It creates a flame (might change it to something else) that can be controlled by the player's direction but slowly vanishes. I accidentally made this while making the bow and arrow follow the player instead of a fixed direction. The wand doesn't use any coins but it has an extra cooldown.

Obj7 ㅤㅤㅤㅤGrappling Hook

This lets you quickly travel to specific objects like trees, chests, and other things. This one has the most functions that are called when launching, updating the chain, grabbing the object, and returning the grappling hook.

Added diving

To add another layer of exploration, the player can now dive into the water. It temporarily makes the player invisible to projectiles and can travel to new areas.

Sorry for the lack of updates. Some unexpected things have happened in the last couple of months which are too personal to discuss. Regardless, I was able to resume this. For now, I can only make much progress on the weekends.

1 Like

Update #6

I know it only has been half a month since my last update but I had an entire week off, so I made the most of it by making another update.

Added Upgrades

Pretend this is an NPC

In the original game, the key can be upgraded by purchasing a better one. I believe having a place where you can upgrade your existing items is a much better idea. You'll also need some crystals to upgrade them, which can be found in chests or bought in shops.

New enemies

ezgif-7-77b76300d8 ezgif-7-2a990f1aea

These new enemies are based on the original. They behave a bit differently compared to the original. Crow only strikes when it has the same horizontal or vertical direction and can only go to two points. The axolotl-looking creature has two sprites that can only attack horizontally or vertically, it also spawns at a random water tile.

Added Item Shops

screenshot (4) (1)

I already had a mock-up for this since September of last year but was too inexperienced to finish it in time, until now. In the original, prices are shown below the item. I didn't want to create too many tiles that were only there to display the prices. To solve this, I made a little sign that not only tells the prices but also knows what item is above and then does the rest. The item in question has an event that has the price, a small description, and if it is limited.

Coins can now be picked up by weapons


You can now pick up coins from any distance with any weapons, including the ranged ones.

There are still stuff I wish I could cover like sound effects but I'm not sure how that would work. With this many features, I could recreate the demo at this point.