Apple II Commander Keen of Concept

This isn't a full demake/game, just a proof of concept.


I made a mockup hi-res image while thinking about the game, specifically told Tom Hall I wasn't going to do this, but then did it anyway.

Legal Note

This product contains trademarks and/or copyrighted works of Id (or whoever owns the relevant IP these days). All rights reserved by them. This product is not official and is not endorsed by them.

Current Status


Recording of version 0.08 (yes I know it says v0.07, I forgot to update that) playing in AppleWin.

Older videos:


You might also want to see some glitchy outtakes

System Requirements


Disk Image


Playing in a Browser

If you don't want to use an emulator / don't have an Apple II at home, you can in theory play in a browser at the internet archive here: keen1_lores at Internet Archive

Frequently Asked Questions

Development Notes

10 May 2024 -- v0.08

Was gradually adding in some of the levels, though they're not fully playable and I'm going to have to update the engine to handle more than 64 tiles.

I did implement the title menu and the story. For the story it's using vapor-lock (reading floating bus to find vsync) to do unusual mid-screen mode change fro text to hires. Writing cycle-invariant 6502 code is always a challenge, especially when you're big enough your branches cross pages. Why do this instead of using hi-res font routines? Just to be difficult I guess (it also scrolls a lot faster)

21 April 2024 -- v0.07

Getting some more interesting glitches, but in theory the engine is generic. Though the Mars overworld could share more common code, and ideally we shouldn't have to re-load the ENGINE file each time as I'm using a stock DOS3.3 filesystem so it has to seek up to the CATALOG track each time before opening a file.

Things were going great until I realized LEVEL15 is 142 tiles wide. Why? My code is optimized great for maps up to 128x80 tiles, this is the only one wider than that. I guess I could go back to 256x80 but that would take up 20k of RAM and not sure I have that much extra hanging around.

You can in theory now pick up keycards and pogo but can't do anything with them.

15 April 2024 -- v0.06

Mars overworld is functional but buggy. Teleporters are working. After a lot of work got Level1 more or less working again (everything broke in the 128x80 migration)

Working on making the game engine generic. Level2 is more or less working.

13 April 2024

Worked on making the Mars overworld map be a proper tilemap, so that we can implement other levels.

As part of this, changed the tilemap code to be 128x80 in size rather than 256x40. This made things more complex (not one memory page per row anymore) and broke a lot of things, but needed to handle larger maps

8 April 2024 -- Version 0.05

Released a version that should have slightly better IIgs support. Haven't tested on real hardware though.

7 April 2024

OK, people talked me into implementing better keyboard support for IIe. It might be a few days until I get around to implementing it.

6 April 2024 -- Version 0.04

I guess I will release this as it's sorta fun to play and hitting diminishing returns with features. Controls are still a pain. Having the yorps run around is fun. Had to truncate the sound effects a bit to not be laggy but they're nice too.

3 April 2024

Been working on this some more. Taking a while as I've re-written some of the core, and also unlike the duke version I'm implementing actual enemies that move.

I also wanted better sound effects, so wrote a tool that takes the sound effects from the original game and dumps them in a format that can be played by a somewhat modified version of Paul Lutus's sound code from the Apple II Red Book. They sound great, but I can't use all of them because the Apple II can't (easily) play sound in the background.

19 March 2024

This is taking way longer than it should because I have been incredibly busy at work.

14 March 2024

Working on this a bit during spring break. Working on updating and documenting the Duke Nukem engine. Wasting a lot of time trying to get the controls to be playable.

9 March 2024

Made the hi-res sample image and posted it online, got enough of a response that I started looking into it.

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