Playing a variety of indie games and remakes now, I would have to say gameplay and difficulty is most important.

Lets be honest, very old games control far worse than they do now and some difficultly spikes are just plain unfair.

If a game is well made with a difficulty that can be overcome with good enough execution and knowing what to do consistently, thats my limit. If it is cheap, then Im out.

I wouldn't say I have a specific cutoff point. The first home game system we owned was a Pong clone, so I can tolerate quite a bit. For me, it's more about having certain preferences. I don't care for ASCII graphics like you see in Roguelikes - I don't know, I just don't like them - and I try to avoid pre-Soundblaster PC games because I can't abide the sound of the PC speaker. If another version came out for another platform, such as the C64 or Amiga, I'll play those instead. I also don't care for CGA graphics.

I'm in my 40's, but I definitely have a cutoff point. I can't do 2-D graphics with anything less than NES quality....and to be honest, that's pushing it to the maximal limit. As far as 3-D is concerned, I cannot go back to anything less than PS2 quality with some rare exceptions. Final Fantasy VII, VIII, and IX are god-awful butt-ugly by today's standards, but they were such good games. These rare exceptions mostly pertain to anything SquareSoft-related from the PS1 era that had those blocky polygons. I cannot and will not ever play DOS based games again. One would think that since I'm so-and-so-years old, that I would be used to less-than. Well, I was used to it, enjoyed the good old days, and grew tired of them. lol I want modern technology, not relics of eons past.

For 320x200, MCGA looked the same as VGA.
https://dfarq.homeip.net/mcga-vs-vga/

If a game supported MCGA that is... few did.

It only sounded "fake" because of the composition and/or sound source(s); not because of the MIDI protocol. Many/most of current game (or movie) soundtracks are still made using MIDI (or similar inside a DAW).

I wouldn't say movies, those usually use a real orchestra. In games it's more often the case, but also very often it's a mix of synthesized music and some real instruments.

Sadly a lot of people these days only know Microsofts shitty Windows MIDI software emulation which really is just there for the sake of it.
Back when it was modern technology, cards like Terratec had a 4 MB soundfont bank and a real MPU401 chip on them. The Terratec samples were among the best back then. I never really liked the Roland sound, it was way too spacy and synthetic. But Roland did co-define the standard which later all MIDI devices used.

I had a SB16 for sound and a Terratec Maestro 32 with deactivated sound module, but active MIDI board which I passed through the Soundblaster :)
AWE (first 32, then 64) was designed to use flexible wavetables, but sadly died rather quickly due to the changes in Windows.

The fun thing about MIDI was that all people had different hardware and therefore the games sounded different on every computer.

These days for DOS and ScummVM games I use - if supported - the excellent Software VirtualMIDISynth and ~500 MB of samples (Arachno and HQ Orchestra, 8MB-Soundblaster as backup). Also some older Windows games on GOG use MIDI, but are set to Adlib. It pays off to change the configuration and direct them to the MIDI emulator.
I also have a USB cable to connect a external keyboard which acts as MIDI device for games, like it was done with the old Roland devices.

Sometimes, depending on the budget and composer. I wouldn't recognise the difference between a recording of a real orchestra and a Kontakt+multi-GB sound library composed score. (or hybrid)

Ok, I was thinking BIG movies :)
You're right, I have seen a lot of movies with very cheap synthesizer music, especially in the 90s.
And it's true, a mix of synth + live instruments can be deceiving (which is it's purpose). In many cases they also just use smaller orchestras or have the artists play multiple voices. In some cases additional synth voices can be heared however.

Do you remember the platformer Heart of Darkness by Ocean Software? That was something special back then, with a soundtrack played by the London Symphony Orchestra. The Shadows of the Empire game / books / comics also existed a CD soundtrack by Joeal McNeely played by the Scottish National Orchestra.

Actually, I don't think those games, particularly FF7, were good games.

In fact, when it comes to the Final Fantasy series, there is essentially a cut-off past which I find that the games just aren't as good as games; I tend to draw the line between FF5 (favorite game of the series) and FF6 (painful until you get the second airship).

What type of keyboard? Is it a typewriter-style keyboard (the sort that you'd use to type this post), or is it a piano-style keyboard?

Unless we're talking about digital fusion, where the synth instruments are clearly not imitating real instruments. For example, maybe you might have an orchestra, but there's also an 8-bit sound channel that gets the melody at some point in the piece, and is treated like just another instrument.

Incidentally, I happened to catch a clip of an educational program where Wendy Carlos had a synthetic instrument that she played in some composition that also involved real instruments.

Well, it has to be a MIDI device. in my case I am using a piano style keyboard, but a drum set works as well, as long as it udnerstands MIDI (edit: although it's probably not a good idea to play Monkey Island's soundtracks with drums only).

Most music is mixed after the recording. Certain classic instruments are very convincing when played through a MIDI devices, others aren't. So - depending on the type of soundtrack - you can use backround MIDI instruments and use real ones for the highlights and hardly anyone will notice. That's used in many games to save costs.

Never played it. I'm not a big fan of platformers, though I played a few when I was very young. ;-)

ps. I was referring to sample libraries earlier, not synths. (this one, for example: https://www.spitfireaudio.com/symphony-complete )

Yeah, thought so. But it's still generated/pitched, right? Or do they have a sample for every possible tone?
And then of course there are various methods to play a instrument. A violin can be played in so many ways...

https://youtu.be/9jHH2kx77hQ?t=4412
It was a spirital successor to Another World with more action and a lightgun constructed by a teenager. You could die in so many horrible ways ...

The big ones have a recording per pitch/note, per playing method, per instrument.

What I'm referring to with "digital fusion" is something different. It's when you have real instruments (or syhth that sounds like real instruments) mixed with electronic sounds that don't mimic real instruments, with the latter having important parts. For example, there's parts of Undertale's soundtrack that are like that; in the Toriel fight music, for example, it starts out 8-bit, but then you get what sounds like strings coming in.

Essentially, it's something like an orchestra, but add some electronic sounds (like 8-bit) as though it were another instrument.
You can have separate instruments for violin arco and violin pizzicato, in your violin example, and that will cover most of what you'd see played in an orchestra. (Although you'll probably want both solo and section variants, as well.)

There's some instruments where the tamber changes significantly over the range, like the clarinet. The lower register and the middle register sound *very* different. And there's other things, like how the middle line B-flat on the clarinet sounds rather stuffy, which of course brings up the question about whether you want to mimic the flaws of the instrument as well.

Including problem cases like the clarinet's B-flat that I mentioned? (You would probably get a much better tone by starting with the B and manipulating the waveform to lower it a half step than by simply recording someone playing the B-flat in the first place.)

Well, there's a lot more than you can do, like only slightly touching the strings close to the body which produces a unique sound and of course different bow techniques which you could partially emulate by changing the star- and end-segment of the sample and fade effects, but it really would be a lot less effort to just use separated samples. One who is not used to hear the difference won't notice of course.

I agree, that for most instruments (like the clarinette in your example) you need several samples for various frequency ranges, many collection do that already.