There is not a lot to laugh about with flat earthers. The theory stems from Christian fundamentalism, and it is tightly connected to the christofascist movements trying to coup the USA at the moment.
And no, they are not going to give up their beliefs, because they didn’t come by them through rational thought, so rational thought isn’t going to disprove it for them.
I don’t really understand what it is about HMMIII you don’t get. It is a relatively simple game concept, and the fundamentals has remained largely unchanged from iteration to iteration. I personally prefer III over most of the later ones exactly because of its simplicity (and none of those ugly 3D graphics).
For me what mostly antiquates a game is if it was primarily based on graphics which have been outdated, otherwise I don’t really have a problem even with much older games. But then again I also grew up playing games in the 80s, so I have been used to those my entire life. Some of the games which fascinated me on account of the complexity, like the early Ultima games (at least I and II), doesn’t exactly stand revisits, because they were very barebones compared to the later games in the franchise. Ultima V still holds up beautifully, simply because it is so complex behind those primitive graphics.