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Alex Kidd on Miracle Island - Playable Demo


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UPDATE 2022-08-01 22:00 HKT:

  • We're back in business!
  • Added invincibility power upp
  • Added an inventory screen: press space bar to open it
  • Added a shop: buy power-ups and extra lives to make it through the three demo levels


UPDATE 2017-10-13 09:00 CET:

  • Still wasn't detecting F18A properly (or, more accurately, failed to detect absence of F18A. That should be fixed now.


UPDATE 2016-04-20 22:00 CET:

  • Now properly detects and supports F18A firmware version 1.6 and up, instead of only version 1.6
  • (Hopefully) fixed a screen tearing issue on the F18A on real hardware reported by Rasmus

UPDATE 2015-10-15 12:30 CET:

  • Fixed bug that lead to garbled graphics on real tms9918a chips and emulators that correctly adhere to the 4k/16k bit in VDP register 1
  • Fixed issue with debris rendering. It should now always start in the right place, and should not fly off of the edge of the screen.






It is with no small amount of pride that I'm posting the first playable demo of my first game for the TI, Alex Kidd on Miracle Island!


The goal of this demo is to gather feedback from you all, and hopefully to wet your appetite for the full game, which I hope to get ready by the end of this year/early next year. Any and all feedback is welcome, from bugs over gameplay to artwork. I can't promise I'll take every single thing into consideration, but I want to make something with broad enough appeal to warrant a full fledged cartridge release, so you can bet I'll be listening carefully.


Please report all bugs you find in this thread, not the main development thread (I will be using that as my development blog for the rest of the game :) ).


This version is likely far from perfect, and there are a couple of known bugs:

  • Sometimes, on the upper four rows of the screen, the collision detection with the scenery can be a bit wonky. It shouldn't affect gameplay too much, but Alex has been seen standing 'over' a piece of scenery instead of on top of it when roaming the top part of the level. If that happens, just move a bit, or jump to a lower platform and everything should be ok. I have not been able to actually get unrecoverably stuck in a level.
  • The debris you see when Alex destroy a box or block may fly off of one edge of the screen and appear on the other side, I'm working on that, just ignore it :).



  • Semi-accurate physics for your player character
  • Three fully playable levels
  • On tms9918a or v99x8 systems
    • Multi-colored player sprite and major enemy sprites
    • Smooth, pixel-perfect scrolling
  • On F18A enabled systems
    • Automatic detection of your advanced VDP
    • Smooth two-layer pixel-perfect parallax scrolling
    • Up to 64 simultaneous colors
    • Multi-colored sprites
    • More diverse sprite patterns
    • Foreground and background tiles, so Alex will walk behind flowers and 'through' grass.
  • Colorful title screen, map screen and story screen
  • Three different soundtracks
  • Eight unique sound effects
  • And likely a lot more... :)


Running the game:

  • Burn the file 'alexkidd8.bin' to a 512k non-inverse '378 style' bank switching ROM cart (these are the red 512k boards and uberGROM, I believe) and play it on real hardware (requires a 32k memory expansion). (Thanks Chris for verifying that it works on the real thing!)
  • People with F18A-enabled systems that want to play the game in the tms9918a mode simply need to hold joystick 1's fire button when selecting the cartridge from the module library menu. Hold the button until you see a black screen, and the game will bypass the F18A detection.
  • The game has been tested and verified on js99er.net, mess and Classic99. Each emulator runs the game equally well, so feel free to use your platform of choice. js99er.net user can enable F18A support to see the game's advanced graphics.
    • In Classic99, use the 'Cartridge' menu, choose 'User' and select the file 'alexkidd8.bin'
    • In mess, use your favorite front-end to run the rpk, or use the following command-line: "./mess ti99_4a -peb:slot3 32kmem -cart alexkidd.rpk"
    • In js99er.net, select "Open RPK Module" and select the file 'alexkidd.rpk'


How to play:

  • Use Joystick 1 to control Alex, the full game will have keyboard support but for now you'll have to use a joystick.
  • Pushing the stick left or right will predictably move Alex left or right. Know that Alex builds momentum and takes a fraction of a second to come to a full stop, just like in the real world, so when making long jumps it might help to take a running start and when coming to a halt don't hesitate to push the stick in the opposite direction to brake a little bit so you don't fall of the other edge of your platform.
  • Unfortunately, our joysticks only have one fire button, which means you have to push the stick up to jump. If you're adventurous and don't mind doing a bit of soldering though, you can create your own two-button stick by adding a second button to your homebrew joystick design and wiring in the second joystick's fire button. The game allows you to jump with the second joystick's fire button for that authentic third generation home video game console feeling!
  • Every level has two differently colored blocks, one of them you can destroy by punching, the other is indestructible.
  • Punch blocks that are in your way, but make sure you don't destroy blocks you need to get to higher places.
  • Collect as much money as you can. Admittedly you won't be able to use it in this demo, but in the full game you'll be able to purchase upgrades, extra lives and gain access to bonus levels with it!




Enjoy! And don't forget to let me know how far you get, and what your high score is!




Edited by TheMole
New version!
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So, my 512k red board boots to the last bank, it seems to me I should be able to copy the first 8k bank to the last, and burn just fine. Is that correct? After the first paging operation if any, then things would be where they belong, as long as the last bank isn't actually required to be unique. I realize there are more direct approaches, but this seems like a quick and dirty technique that should work.

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I finally got downloaded and tested here, it's working for me even with F18A GPU enabled. I have v380 on this computer, I can't try the latest till later.


v382 here.



I guess I should add that I unzipped the RPK and used that, since it was a smaller download and the internet is a bit sketchy today. ;)


I just tried that. Same problem. I will try on another computer. Wish I had a way to put this on iron.

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I get scrambled graphics in Classic99.




You get this as the game starts up? Could you try bypassing the F18A detection by holding fire when selecting '2' from the cartridge menu until you see the title screen?

Also, when you press fire on your joystick, does the screen change? Do you hear the music?


Sorry for the barrage of questions, just trying to pinpoint where it goes wrong.

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For MESS you can also activate the 32K console mod in the OSD menu.


If I may add a suggestion: You should check for the memory expansion right on start and print something like "NO MEMORY EXPANSION / PRESS QUIT".


That's a good idea. I'll probably have to either write a small piece of assembler code for that or fiddle with the linker script some more, but it shouldn't be too hard.

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very nice work the Mole !

i must say i played it before in TMS99xx mode, and it was funny, but after, i tried the F18A Version and WOW ! it is Fantasic ! ... i can't believe this is for the TI-99/4A :)

i can't waiting to see this game in one of my cartridge :)


THANK YOU for this piece of gold of programming added !!

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For those that are seeing corruption or having troubles burning, I've added md5 sum for both binaries. I downloaded both from the forum here and compared them against the files on my computer and they are identical, so the upload was not corrupted.


I also noticed that I actually inadvertently uploaded a test version, which makes the 'debris' bug mentioned above even more apparent. I'm not uploading a new version for now until I've guaranteed that the people who are having trouble running the game are helped as well.

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v382 here.




I just tried that. Same problem. I will try on another computer. Wish I had a way to put this on iron.


Okay, I just tried again on Classic99 v386 (latest) using the Alexkidd8.bin download, with the F18A GPU option both on and off, and it worked correctly here. I'm not sure what you're seeing, OLD CS1, can you try the latest Classic99?

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Lucky, I'll have to settle for emulation as I can't burn cartridge


Wish I had a way to put this on iron.


If it helps, I haven't been able to run it on The Real ThingTM either :). But yeah, I know it's a bit of a pain not being able to run this from disk, I'll try to minimize the number of image-only demo releases.

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You get this as the game starts up? Could you try bypassing the F18A detection by holding fire when selecting '2' from the cartridge menu until you see the title screen?

Also, when you press fire on your joystick, does the screen change? Do you hear the music?


Sorry for the barrage of questions, just trying to pinpoint where it goes wrong.


This is after selecting the game in the menu, music does play. I tried bypassing F18A detection and get the same thing. Pressing fire on 2 does nothing, but pressing fire on 1 starts the game. The screen changes, still scrambled, and I can hear sounds.

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