I somewhat enjoy the idea of curating retrogame collections but it is very tedious, trying to find the perfect balance of abundance and simple discovery. There are very obvious diminishing returns when it comes to larger libraries of games. Simplicity and abundance are in opposition.
Many interesting systems and mods have come out in recent years. The ecosystem appears strong. I want to highlight two particular systems that are built by british enthusiasts, turned into products.
From retrocollective this unit is manufactured using well tested boards and a company's 3D printing farm. Lots of attention to detail.
This project turned product is meant to provide a retro experience where it had been lacking, in monitors. Something that could give you inputs for nearly all the systems you'd ever need and modular to accept other technology ports too.
Like systems I have used to have a LOT of controllers too. You might say I have a bit of a collection of controllers. One of the disheartening things is that the old classic controllers I have from the commodore / atari era almost all of them were made in USA.
List of software packages that would allow somebody to get a large, complete or robust library of any given system. Some of these below contain the games, others are more of a multi-emulation system.
A list of the retro or mini consoles I have:
The A500 mini is interesting in that it looks like it has a keyboard, but in fact it's just a facade. But Amiga games are ones that sometimes require more complexity to work. The A500 mini has some software mods available for it that are worth looking at and loading onto USB sticks. Because all the builds below bring interesting features, it may be worth having all of them on shared or separate USB drives in order to use. For example, Pandory once configured has retroarch and will play more games and have support for different game controllers.
Aminimiga seems to be a build based on a classic amiga desktop with mouse support. Amiga Game Selector seems to be an entirely different way to open a large library of Amiga games to play.
The C64 Maxi has the working keyboard and has similar software and controller as the c64 mini, (which I sold). There is also other software that can be added to the c64 maxi, and of course more games can be added. Controllers supported, you can use the A500 game pad or even a PS4 controller.
The Genesis mini is hackable via the Hakchi software. More games can be added, thumbnails customized and retroarch installed. A separate project from Hakchi is called project Luna which also adds Retroarch and thus, more playable console and arcade emulators.
Without getting to attached to platform, it's a fun exercise to come up with some game ideas. These would be games maybe I would make if I could, or games I'd like to see exist.
This would take a concept of construction that would be done quickly so as to mock up layouts. And perhaps it would be based on tiling just like a lot of games, but maybe you could create your own pixel art tiles and customize the game as you like. The restrictions would be based on whatever system you're trying to implement. So if the system couldn't handle the number of sprites needed or tile maps, then that system would have that restriction.
Ideas would be for home layout, room layout, van or RV layout. property builder. For these maybe the sprites could be furniture, cabinets, fixtures. It seems like most computer systems could handle it if you consider the nintendo NES game excite-bike allowed for course building and though it was a limited number of track ramps and obstacles, you could build a good length of track.
In this game, you're in Japan and you have to dodge the souvineers. The game “enemies” are the typical souvineers you'd see in Japan. This could be China or Mexico too, just the sprites have to be created as such.
Combine some of the mechanic of Flappy Bird (always scrolling background) with Joust where you have to be above your enemies and hit them to get points. Also it could be you have to go upward just like the joust platforms instead of sideways. Perhaps part of the underside of the platforms can kill or trap you through the every scrolling floor. Some other mechanics might be if you collect or land on certain things you are stalling the scroll movement. In the world of Joust, you are in an area with lava pits, so it could be rising lava forcing you to flap upwards around platforms.
When you're fooling around with old systems there should be casual games to play. Something that shows nice environments and having calm mechanics. Maybe there aren't enemies, maybe you're just tilling land, maybe there's no points. It might just be a kind of habit of movement. Mowing grass, chopping wood. The bamboo mini game in Ghosts of Tsushima is a great example. It's fun to do the button timings and then maybe that's enough for the game. If there's any progression to be had, it could be something akin to a morning refresh. Like a game of solitaire.
Think of the hunting mini game in Oregon Trail. It's fun and the only downside is you lose a day if you don't get anything. Now in Oregon trail, seems like you have no reason to over hunt but you're limit is lbs you can carry.
Scenario based game where you try to adhere to a certain likely incentive and outcome.
In this game you learn about alternative or unusual historical things. Somehow the game will have to find ways for you to accumulate and know your progress. Maybe through testing of some sort. Interesting graphics would be key here as you'd want to illustrate scenes with cute pixel art. Think bible stories or other early history and how pixel art and animations could be constructed.
This game would be based on a series of connected services to keep the game fresh. The system itself wouldn't be able to handle the processing so the game could be refreshed by leveraging A.I. and automated story and image generation services. For example, A.I. would generate a story, and then create an image and that image would have to be converted and somehow dumped into your system or acquired from a source your older system could use. Let's say your system can connect to an old billboard service. Could the updated file be grabbed from there? Or could there be a process which the service has generated many of these stories and you can continually download or refresh with a new disk periodically grabbing from internet to SD card. Could be simple as limited paragraph text on top of a single image. And a sequence builds like a comic.
This would be a casual game where you are collecting and disposing of garbage. Maybe you can set up various sytems and it could be connected to a resource system where you earn money and can buy more cans, more trucks, more disposal trolleys, more landfill property. Who knows. As things pile up it could be a bit of a panic too. Perhaps if clutter starts to accumulate, other things worsen. Let's say like Simcity, there are complaints or accidents or lost customers. Consider the game paper boy where you see the city block and the houses that are customers.