Cosmic Payback ZX81 (coming soon...)
Cosmic Payback ZX81 (coming soon...)
Hi all,
I'm pleased to announce that I will soon be releasing a ZX81 port of my Spectrum game, "Cosmic Payback", a 3D platform-puzzle game involving a bouncing ball in space.
I had originally intended to release this today, the 5th of March, in honour of the ZX81's 44th anniversary. However, there are still a couple of parts left to implement - and very little memory left for them. That being said, I didn't want the day to pass entirely unmarked, so I've decided to release a small three-level demo of the game to let you have a go at it prior to the full release.
The full version will be released on the 30th of March. That should give me enough time to get all of the loose ends tied up so that I can present the game how I would like to.
In the meantime, I hope you have fun with the demo here! The keys are as follows:
Q - up / A - down / O - left / P - right
EDIT: New version of the demo uploaded - patched to fix issue with star graphics when loaded with ZXpand.
I'm pleased to announce that I will soon be releasing a ZX81 port of my Spectrum game, "Cosmic Payback", a 3D platform-puzzle game involving a bouncing ball in space.
I had originally intended to release this today, the 5th of March, in honour of the ZX81's 44th anniversary. However, there are still a couple of parts left to implement - and very little memory left for them. That being said, I didn't want the day to pass entirely unmarked, so I've decided to release a small three-level demo of the game to let you have a go at it prior to the full release.
The full version will be released on the 30th of March. That should give me enough time to get all of the loose ends tied up so that I can present the game how I would like to.
In the meantime, I hope you have fun with the demo here! The keys are as follows:
Q - up / A - down / O - left / P - right
EDIT: New version of the demo uploaded - patched to fix issue with star graphics when loaded with ZXpand.
- Attachments
-
- CosmicPayback_Demo_patched.p
- (15.93 KiB) Downloaded 1037 times
Last edited by PROSM on Thu Mar 06, 2025 9:51 pm, edited 1 time in total.
My Sinclair software to-date
Working on something, as always :)
Working on something, as always :)
Re: Cosmic Payback ZX81 (coming soon...)
Woaw, this amazing ! I found it to be a little difficult, maybe I'm just too bad.
This seems like a masterpiece !
This seems like a masterpiece !
Re: Cosmic Payback ZX81 (coming soon...)
Just when you think nothing else was possible with the Zeddy!
I shall try this on real kit tonight.

I shall try this on real kit tonight.
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Re: Cosmic Payback ZX81 (coming soon...)
The game looks great, has really nice animation, and plays very well. At first glance, it is easy to miss that it is pseudo hi-res! An excellent job! Looking forward to the full release.
Re: Cosmic Payback ZX81 (coming soon...)
Yep works on real zeddy and ZXpand, what I imagine are the stars in the background turn into lines as it runs so not sure if that is normal or not, otherwise yes great stuff.
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Re: Cosmic Payback ZX81 (coming soon...)
Yes, my apologies for that. The trouble seems to be caused by the ZXpand overlay ROM - I've now patched the game to disable the overlay (new version in 1st post), and that seems to fix it under emulation.
EDIT: Over on the Spectrum Computing forums, flange has been helping me with testing, and it seems that the issue persists on his setup, even with the patch. I'm going to have to investigate this further...
My Sinclair software to-date
Working on something, as always :)
Working on something, as always :)
Re: Cosmic Payback ZX81 (coming soon...)
Flange/Moggy one and the same sir!PROSM wrote: ↑Thu Mar 06, 2025 10:03 pmYes, my apologies for that. The trouble seems to be caused by the ZXpand overlay ROM - I've now patched the game to disable the overlay (new version in 1st post), and that seems to fix it under emulation.
EDIT: Over on the Spectrum Computing forums, flange has been helping me with testing, and it seems that the issue persists on his setup, even with the patch. I'm going to have to investigate this further...

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Re: Cosmic Payback ZX81 (coming soon...)
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert 
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp


There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb

Spring approaching...
Re: Cosmic Payback ZX81 (coming soon...)
Funny that - I noticed your signature both here and on SC, but never made the connection!

My Sinclair software to-date
Working on something, as always :)
Working on something, as always :)
Re: Cosmic Payback ZX81 (coming soon...)
the zx81 can't do 3D but i'm impressed. Will you be doing ports to other systems like the Jupiter Ace or Sinclair QL?
In Heck, there are two options for perpetual torment:
Eat the Puckerberry and suffer for eternity:
drink nothing but a cocktail of The Last Dab and Mexican Cake blended and served with
habanero slices

Eat the Puckerberry and suffer for eternity:
drink nothing but a cocktail of The Last Dab and Mexican Cake blended and served with
habanero slices
