Binding Of Isaac creator Edmund McMillen doesn’t like the word ‘addiction’. But I do. It’s the only word I can use to describe my frankly irrational gaming behaviour over the last seven months. The Binding Of Isaac Rebirth has taken over. I’m more at home in the Basement or the Cellar than I am in my new flat. My thumbs twang with the memory of the repetitive strain injury (RSIsaac) from long winter nights spent firing tears at furious faeces. Versions of the Four Horsemen so noisily disturbing that I heard their cries long after I had switched off the PS4. And don’t even start me on Mega Satan. I won’t stop.

One man is to blame and when I speak to him, it suddenly all makes horrible, horrible sense. ”I made this game completely for me,” creator and designer Edmund McMillen quickly admits, having somehow agreed to speak to me about my problem.

For those who haven’t had the pleasure, Isaac is the young son of a fanatical Christian single mother who believes after a message from God that she must take the life of her child. He ends up in the basement of their house, battling the demons who reside there with the only weapon he has, his tears. You can see why Nintendo initially said thanks but no thanks.

Rooms of living faeces, evil clones, scrabbling spiders and fiendish bosses await. It’s a simple enough set up. Clear the room, the doors unlock, repeat. Permadeath is the order of the day. Each enemy damages you half a heart (initially) and the juggling of items such as bombs, keys and trinkets mean you’ll never play the same game twice. It’s a world of procedurally generated darkness that will drive you slowly mad as you discover how far the demonic rabbit hole actually goes. Spoiler? Far. It goes far.

“I think the thing that keeps me coming back is that I play it as well,” ponders McMillen when I ask why he’s still making content and new versions of the game (Rebirth has just released on Xbox One and the New 3DS). “I think also my wife, like you, plays religiously and it’s fun to watch her play. That was one of the reasons why I added co-op so when she was playing I could just pop in and mess around.” This isn’t just a game he created, this is a game McMillen still plays and has updated to suit his tastes.

And initially it was only for his tastes. “I thought only I would like it!” laughs McMillen. “It seemed too difficult, it seemed too unforgiving. That was kind of the initial response when it came out. We had people like ‘Oh I like Meat Boy, so I’m just going to buy this’ but there was a lot of push back. It takes a little bit to hook ya. For it to fully unfold...”

Unfolding is the key to Isaac. Like one of those beautiful Japanese flower teas but with faeces, vomit and dead children. Initially there are only five floors to finish. A descent through the floors (each with its own boss) culminates in a battle with Mom - a stomping, enemy-spawning behemoth with high heels - and beating even that feels like a towering achievement. Dependent on your pick-ups, by that point you can be armed with up to twelve hearts instead of your starting three, have flaming tears, be leaving behind a trail of tar, have a familiar that fires lasers... or perhaps you’ll be steering one giant tear while riding a pony you won from a toxic horseman.

And while beating Mom might be the end of the game for you it’s not the true end. That’s far, far away. “The first time you kill Mom is just the first unlocking of the game,” confirms McMillen. “And I designed it in a way that it would keep unfolding the more and more you play.”

Beyond Mom lies two levels of Utero and the chance to defeat Mom’s Heart, a spewing bullet hell of a Boss who spawns laser firing eyes. And then? A chance to ascend to The Cathedral to tackle an angelic version of Isaac himself, or the ability to clamber deeper below and take on Satan. And then? Collecting six pieces of a Polaroid. And then? The transformation of Mom’s Heart into It Lives. Two pieces of a key. The Blue Baby. The Lamb. Mega Satan. The Lost. How deep can you go? How long can you survive with what you’ve got? Be afraid. This game is dangerous. Die and you’re right back at the beginning. Live and you might just watch the credits after one of sixteen endings, roaring triumphantly.

“You need the understanding that this game doesn’t play like other games,” explains McMillen. “You’re meant to lose. The excitement is in the next run. Not in the initial. It’s always the next run that you’re excited about because of the possibilities that are endless.” And here’s where the addiction lies. It’s where my thumbs twitch at even the mention of Isaac. Just one more go. Pure addiction.

“I try not to use the word addiction!,” howls McMillen. “My goal was never to make a game that was addictive! Like I’d hate to think that people are staying up endless hours of the night playing this game. But for me - and it sounds narcissistic at this point - I would much rather play Isaac than almost any other game out there. There is not much that compels me and I feel, to some extent, spoiled by what I have done because I have made something that I can enjoy - and if I enjoy it enough then I can enjoy it forever.”

These are truly terrifying words. I can see my future from here. A gaping maw of Isaac looming to swallow me whole. I can’t be a games journalist if I don’t play any more games. I’m a shark. I was never meant to stop. How can a glorified twin stick shooter do this to me? “That was my kind of goal,” he continues, oblivious to my plight. “Like I want a game that could almost be a forever game. This evergreen game that you can keep coming back to, much like Pacman. Something that has random generation that can keep you going forever. For me it’s just that I’d rather just do that. It just seems bite-sized but endless.”

When I ask if he is ashamed of what he has done to me, he pauses. "To some degree, yes. I mean there’s a certain responsibility of the designer when doing it. I mean, I could say that it could have been much worse. I could have been, y’know, charging you for lives or something along those lines which is way more despicable. Ok, I realise that there’s a slot machine aspect of the game that’s very strong and the random generation definitely kinda gets you going, but I feel like ‘addiction’ had more negative connotations. ‘Compelling’ has less. I don’t want people to just waste their lives playing something! It doesn’t make me feel better to know that people are really pouring five hundred hours into the game. But, I did make it so it goes on forever...”

Speaking of forever, McMillen is currently working on the aptly titled Afterbirth DLC, with more items, more bosses, more trinkets, and absolutely no consideration for the thumbs or professional lives of its players. He's been taking feedback from the community too. Enlisting help to add to Isaac’s random arsenal with new items such as Pokeball style throwables that trap enemies for use against foes in another room. But McMillen’s having trouble stopping adding content.

“We’re pretty close [to finishing]”, he ponders. “I just got a message from Tyrone that says ‘I think we can do 30 more items.’ I kind of went in a bit crazy with a hundred plus items, and then there were ten community items that I put in and I was like ‘ok this is good’. But then one aspect of the game is that when you have new characters you have new places for unlocks, and I’m a stickler when it comes to reward. I want there to be a reward in the game for everything you do, and again the game’s based around expansion the more you play. So if there are new things to complete, then each character has to have some kind of unlockable item per thing. And if I’m adding a bunch of those things then maybe thirty or so items are just going to be locked, so that’s no fun. I think we can do more of those. The goal is still summer. With Afterbirth, I’m excited. I’m excited to play it.”

I’m looking at the arrival of Afterbirth with a burning desire and I've been longing disturbingly over the Binding of Isaac official site where there are gifs of new items. Now that I’ve unlocked all the endings by beating the last enemy of the game - Mega Satan, who despite sounding comedic is anything but - I want more. More than what I’m left with. Which is the impossible task of completing the game with a character called the Lost. One that doesn’t have a single heart of health. Here is where a deeper madness lies but it’s all part of McMillen’s game ethos. “I feel like difficult games are important, especially nowadays when everything holds your hand or you can even pay to complete,” he ponders. “I feel like it kind of really moves away from what games are. People don’t play competitive soccer because they get to win. You gotta play hard. Then it feels good when you win. And I feel like that it’s that same basic thing. No one runs a marathon because everybody wins and you finish it instantly because it’s easy. You’re compelled to do something difficult because it feels really good when you finally do it. And it’s missing from a lot of games.”

Missing? Games? I am missing other games. After the defeat of Mega Satan, I think Isaac can rest for a while. Stay in the dark. There are still some challenges to do, but when Afterbirth arrives, I’ll catch up. Perhaps it’s time to leave the basement and step into the sunshine. Y’know. Just for a little while. Oh, you're just starting? Good luck. You'll need it.