Playing video games with my 22-year-old son has brought me to tears | Dominik Diamond

I have spent the last three weeks living with my 22-year-old son in a two-bedroom flat he has dubbed the ”brotel”. We cook curries and watch Lanterns . We barbecue meat and analyse Tarantino movies. We get pizza and we play video games. Boy, do we play video games!

The first game I ever played in co-op with him was Call of Duty: Modern Warfare 2 in 2009, when he was five. He wasn’t the most accomplished sidekick, not so great at placing a mobile gun turret while under fire from what seems like a bazillion enemy soldiers, but we had a laugh. It started the video game bond between us before his sister introduced him to Banjo-Kazooie and Rayman, and he stopped being a preschool warmonger. Probably for the best. So how would it be tackling the same game nearly two decades later?

We start with the two Special Ops missions we used to play. We never completed them because, once again, he was five – and I am left-handed, which makes me rubbish at joypad-controlled first-person shooters without the help of auto targeting. Thankfully, one of those circumstances has now changed.

Guard dogs in the snow … Call of Duty: Modern Warfare 2’s Evasion mission. Photograph: Activision

The first mission is officially called Evasion, but to us it has always been “the guard dogs in the snow”, because they got us every time we played. Our initial attempts highlight the differences between us as gamers. And men, if I’m being honest.

I am paranoid. I sense calamity around every corner, so I creep forwards, mostly crouching, frequently crawling on my belly, slowly and carefully scouting for enemies using my sniper scope. Charlie is running through the level firing from the hip like Leeroy bloody Jenkins . Which means he alerts all the dogs, who for some reason are able to smell me from miles away and nom nom nom me to oblivion.

We fail. We fail again. But we are having so much fun.

Teamwork eventually emerges through compromise. He holds back a bit, I grow less timid. I snipe from a distance, he finishes them off up close. And, most importantly, we take out the guard dogs first. We realise that was where we went wrong two decades ago. These dogs are superhuman. I would love a level where you got to play as them.

We finally complete the mission. It has only taken us 17 years! We go straight into the other level that we never conquered: Homeland Security, AKA “defend the garage from five waves of attack”. This takes a fair few goes, but we have such great communication by this time that it’s never a chore. We leap from our twin La-Z-Boy chairs in celebration when we win.

We gambol through mission after mission. Suspension, AKA “bridge with helicopters”, is a riot from start to finish. We have a great rhythm. I bazooka from afar, Charlie sprints in to mop up. In Snatch and Grab, we take a computer file then boot it from an aircraft graveyard, avoiding helmeted Juggernauts; it’s pure unadulterated gaming joy. Even when, once again, we fail.

As I am writing this, thanks to whatever AI is lurking in my computer scanning everything I type or possibly even think, an article pings up about the online gaming cheat industry, which is now apparently worth $8.5bn. I’m sure there are reasons why people invest so much money in cheating – but talk about ripping the soul out of something fun.

A familiar sight … Call of Duty: Modern Warfare 2’s multiplayer. Photograph: Activision

I have loved these last few weeks gaming with my son. I feel like I have gone back to basics. After decades as an uptight stressed dad, I am finally carefree, because I have recently gone back to working for myself. And I am a very forgiving boss. Sitting there with pizza, beer and another bloke, playing games till the wee small hours without a care in the world … this is what gaming was like for me when I was my son’s age.

I’m not sure you ever top that period in your life as a gamer – when you get that first job that allows you to leave home, get your own place, buy whatever game you want and play it to your heart’s content, before you become burdened by the responsibilities of relationships, mortgages, parenthood and, worst of all, ambition.

When those things arrive, you are lucky to squeeze in an hour of play here and there. You just try to get as far through a game as you can in that time because you don’t know when the next free hour will come, and you still feel guilty because you feel you should be doing something more grownup instead. You know, something that might help pay the rent.

Now, though, I am back in gaming heaven. It won’t be for ever: my son and I are due to move to different parts of the world in a few months. But he turns to me after one session and says that he will look back on this as some of the best times we ever had together.

I turn my head because I am still a Scottish dad and I don’t want him to see me cry. Even if those tears are the most beautiful big, happy ones.

Copyright for this text belongs to The Guardian.