Last week I saw a post on Ars Technica about a game esecially written for the

HP 200LX

This portable PC with an BW LCD screen, powered by 2 AA batteries is a real PC with MS-DOS. The speciality is that it uses a proprietary driver for the screen. The game is called Lair of Squid , a maze game in the ROM of the portabel. Read the whole article here: https://arstechnica.com/gaming/2024/07/how-i-found-a-forgotten-squid-based-ode-to-doom-on-a-1994-palmtop-pc/2/

I was not aware that the screen is driven by some special chip, so I tried to fire it up on my own LCD portable (CGA capable). No need to say that it didn't work at all.
The version found on archive.org uses a screen driver emulator called CG.com, which must have been provided by HP itself to use the apps also on a normal PC. Sadly this program did not work on my LCD portable.
So I dug deeper in the rabbithole and found a whole HP portable universe. hundrets of programs specially written for these devices... and different screen emulators, also to be used my my little portable: I present to you:
The lair of squid on my okano PC-100

Also I repaired the serial null modem connection of my device to my PC to transfer programs via Xmodem (slow, but hey...)

Now go on, have fun tinkering with old computers!