First of all, thank you so much for featuring the game in your stream!
I see that people are struggling with controls, so I've already added a small bar below every pop-up menu with instruction to navigate the menus as you can see from the attached image.
About the problem with the load/save, the game is asking for a certain device/path but honestly I don't know why since everything in the game is path relative, it should search, from the game path, the <slots> folder.
About the graphic glitch you had, it seems left by the exclamation mark: let me know if you have tested the game using an emulator, it may depend by the blitter settings.
You mentioned controls... well, adding joystick/pad is not really good to me because in some rooms you have to move your character to escape bullets (keyboard) and aim & shoot to enemies (mouse), but I'm open to any idea you could suggest to add alternative controls.
The mouse is only used for aiming, left click to shot at them (the bullet will hit everything between the gun and the mouse pointer, so you can aim also behind the enemy).
The right mouse button is used to use the secondary weapon or device (like the hacking tool or the teleport), but it is not present in the demo.
I think I add controls for left-handed people, but pad+mouse... I think it cannot work.
I think I'll also add quick device/secondary switches mapping them on the numeric keys: in some areas you may prefer to teleport away from an enemies nest :D
The demo is pretty old (August 2025) and in the meanwhile I've fixed/added a lot of things, especially the ones reported by the community. I should update it :)
I'll subscribe on your channel! Thank you again and keep reporting bugs, it's really important to deliver the best quality!