Spelunky is a little clockwork world in which items and enemies behave in defined ways, but when mixed together cause a delicious feedback loops that you can, with experience, predict. My boy loves systemic games like this, games that are built on coherent systems that you can play in an open-ended way. Toy boxes like Minecraft and Plants Vs Zombies, Animal Crossing and (we play this together) Civilization – where he can tinker and learn cause and effect.

He spends hours playing them, or would if we let him. And these are the kind of games that, though they were much cruder back then, I liked when I was a boy too, especially Elite. Where anything seemed possible.

But the big games today, in which play comes fixed to immutable stories, aren’t like that. So I asked him: “Do you like games that tell stories that you follow as you play them, or do you like games that let you do what you want?”

“The second one.” My heart burst with pride.

Last Day Of School, from lovely chum Alex Wiltshire.

The big computer games I grew up with – the ones that made an impression – were Rogue, Prince of Persia, and countless flight sims (beginning with MS Flight Simulator 3.0 then 4.0, and then getting steadily less realistic through the MicroProse back catalogue). And there, really, is a lot of the things I like: deep systems, short repeated play sessions, complex things to master, coupled t worlds to do whatever you want in. I got to about level 14 of the dungeons of Yendor; I landed a Cessna 182 on a Nimitz class carrier without an arrestor wire (only just) and took it around the Michigan bay; I explored the deep 60-minute run/jump mechanics of Mechner’s early triumph.

My tendency to simplification as I grew up has a lot to recommend it – in particular, desigining for sofas or tiny bursts – but my heart swells too when I see the conversations Alex and his son have. Not just because of what they like – but because of how they like it, and, most importantly, how they talk about it together.