Until recently, I'd never stopped to think about all the eccentric conversions that made up so much of my early gaming life. And yet they're everywhere - you can't talk about console history without dwelling on the arcade ports that propped up the back catalogues of the NES, SNES, Mega Drive - indeed, any piece of hardware you care to name.

And these things are fascinating, sometimes falling well short of the mark, sometimes coming up with ingenious solutions to squeeze an all-singing, all-dancing arcade game down on to more humble machinery, and sometimes - just sometimes - earning the mantle 'arcade perfect'.

David L. Craddock, a prolific author and historian, has recently compiled a fascinating account of the history of arcade ports in Arcade Perfect: How Pac-Man, Mortal Kombat, and Other Coin-Op Classics Invaded the Living Room - which is out right now. It's a brilliantly detailed read, allowing us to hear first-hand reports on the trials and tricks of those who were often tasked with the impossible. I got to have a quick chat with David for an oversight on the book, and some of the stories contained within (and, of course, if you want to read them in full you'll have to pick a copy up for yourself).

I'll start with the term arcade perfect, which is of course the premise of the book and the title itself. It's a term you don't get banded around so much these days. What does it mean to you?

David L. Craddock: You're right, it's a term we don't hear so often these days and I kind of missed it. Back in the days of 8 and 16-bit consoles, especially 16-bit and 32-bit, arcade perfect meant this port of an arcade game was as close to 1:1, as close to the arcade game to be identical. As a kid it was really important to me - you only have one system, and playing into the console wars era, you hoped to get the best version. And as a kid, sometimes I did - I had Street Fighter 2 for SNES, but I had Mortal Kombat for SNES and that version wasn't as good as the Mega Drive version as that had blood and all the fatalities. It's just something that interested me, and as I got older I was less interested in 'winning' as I was curious in an academic sense on the differences. Why did the Mega Drive version look different?

I wanted to write a book that charted the evolution of that term, where back in the 2600-era, games like Space Invaders came close, but in some ways, big and small, they were different. Going from there, to each console generation, seeing how games equalled and then eclipsed the arcade version. When people use that term, they're talking audio visuals - games are a visual medium, and it's how big are the sprites, do the stages look the same. One thing I found interesting, as early as the 2600, a lot of ports of arcade games were different in terms of gameplay, and arguably better. Teenage Mutant Ninja Turtles 2 for the NES, you couldn't play with four players, but you had stages that were double the length, new bosses, new cutscenes, new levels. Even for someone like me who'd dumped a lot of my parent's quarters into the arcade machine, that experience felt better because of there was more of it to enjoy.

Yeah, they're almost different mediums when one is trying to get you to hand over quarters - well, for us it would have been 20p pieces - and that's different to trying to get someone to hand over 50 or 60 dollars. They're very different propositions.

David L. Craddock:Exactly! Even back then I'd try to put myself into a developer's shoes. If someone's buying this game and never have to feed another quarter into the machine, how can I make it engaging. If they can just keep using continues until they beat it, that's not satisfying, and so things like new bosses and new levels were a way to keep people engaged even if they were very familiar with the arcade source.

I'm going to show my age a bit here - I had the Atari 2600, which obviously had a lot of arcade ports. I don't think any of them could quite claim to being arcade perfect. I remember Pac-Man, though, which was famously not a perfect port, but it was my only experience of Pac-Man - so when, years later, when I saw the arcade Pac-Man, I was confused by it. I didn't quite know what to make of it.

David L. Craddock: That happened to me with Double Dragon. I only knew the NES game for years - when I saw the arcade version, I didn't like it as much. I know the NES version is considered inferior by a lot of pundits because you don't have all the attacks out of the gate, you have to level up. But I liked that aspect of the game. You mentioned Pac-Man on the 2600, and I'm glad you did. That's something I wanted to lay to rest with this book - I spoke to Tod Frye, who programmed Pac-Man, Garry Kitchen who made Donkey Kong for the 2600, those are two infamously terrible ports, but I wanted to show people that they did not have an easy time. It was really hard to cram an arcade game into these little cartridges that were so inferior to arcade hardware.

Yeah, it's a phenomenal achievement. I don't want to cast any aspersions on these developers - they were tasked with the impossible, and it's fascinating to see the creativity of these people when trying to do these impossible tasks.

David L. Craddock: Yeah, and also talking to them about their perspective of their peer's work - I captured a meeting between Garry Kitchen and some executives at Atari, because after he finished Donkey Kong he was being courted by Activision and Atari. That's another thing - not just anyone could make Atari games, and Garry was one of a select few who could do that. Atari said we hear you want to go and work for Activision, why don't you want to work for us? And he said he thought Pac-Man, which had just come out, was a piece of junk - well, he used another word - but the interesting thing was, he admitted that back then he was so full of himself because he was one of 15 people that could code for the 2600, and he'd never considered that Tod was under so many constraints. And he'd find out in a few months that people weren't exactly thrilled with his Donkey Kong conversion - maybe even less so than they were with Fry's Pac-Man conversion.

Sometimes the more limited the hardware they're trying to convert it to the more interesting it is. To one extreme, I guess, is things like Tiger Electronics' ports of Virtua Fighter, stuff like that. It's mad that someone would set about doing that in the first place, but it's fascinating to see how they go about it.

David L. Craddock: It is. One common theme is that a lot of these programmers assigned to these ports were quite junior, and had never done a commercial game before - and here they are, at their new job, being told hey, make Double Dragon work for the ZX Spectrum, or make Pac-Man for the Atari. The other thing you have to consider, Pac-Man was a big deal but Tod Frye said that he figured as long as he had a maze and four ghosts, that's it - who cares what colour the maze is, what colour the walls are. Now we have people going over the importance of these details, and the minutiae of them. Back then it was a job, they worked under tough conditions with barely any resources. Publishers would be like, well we could give you double the cartridge ROM size for Donkey Kong, but people are going to buy this anyway, so who cares.

We spoke a bit about Mortal Kombat. There were arguments between people about the differences between the SNES and the Mega Drive versions, obviously the SNES one had no gore. While everyone was having that argument, I didn't have either of those consoles. I just played the Game Gear version, which I thought was really good.

David L. Craddock: I did too! It's funny, the ports of Mortal Kombat, it's almost charting my history of getting consoles. When the first Mortal Kombat came out in August 1993, I only had a Game Boy. That version was not good. But I convinced myself that it was because it was all I had. Then a year later I had a Game Gear, and I loved that version. I thought the graphics were good, I had the blood code finally. And then I got a SNES, and it was interesting - I think that's when I started debating more with my friends, really dissecting these things. I'd point out the SNES controls weren't very good - I talk about why that happened in Arcade Perfect - and the sound effects are there, it has more audio samples, the graphics are almost arcade perfect. It just had no blood. Then I got a PC, and the DOS version of Mortal Kombat was arcade perfect - it was incredible for the time, and I couldn't believe I was playing an arcade game at home. But the controls were really hard to wrangle. I was fascinated by all these little differences.

What, for you, stands as the ultimate arcade perfect port? Or is it always a case of interpretation?

David L. Craddock: It's a lot about the interpretation. We had these different experiences of Double Dragon and Pac-Man, and didn't even know about the arcade versions at the time. I think maybe, objectively - and I know that Digital Foundry has written about this, and I quote them - I think it was SoulCalibur for Dreamcast. That's where we went beyond arcade perfect, it added all these new characters, these new modes, and all the assets were rebuilt from scratch and they looked so much better than the arcade game.

Funnily enough I've been talking about some Dreamcast ports on the site recently. Virtua Fighter 3 is a game I adore, but it never really got a decent home port - because of it was running on Model 3, and then the Dreamcast version which was obviously running on something closer to Naomi, it couldn't recreate that experience.

David L. Craddock: Yeah, it was difficult back then. I mentioned Mortal Kombat for PC - looking back, that was maybe my first brush with an arcade port. But if we're talking consoles, something that measured up to the arcade, it might have been Street Fighter Alpha. Other than loading times, that was an arcade perfect port.

What arcade port took the most liberties, and moved furthest away from the source material?

David L. Craddock: This being a case of interpretation, I'd say Donkey Kong for the 2600. When I spoke to Garry Kitchen, he said he put all his resources into making the ramps on the first level slanted. It's something the Atari wasn't built to do. The playfield, they had 40 bytes for the display - 20 for the left, 20 for the right - and they were built to mirror each other. You can see that in games like Pong and Combat, the games that console was made to play. Everything else was a square peg in a round hole. Slanting the ramps so that some went down the left, some down the right, it took up so much cartridge space he had to leave out animations, whole levels. I remember playing it - it said Donkey Kong on the cartridge, but it was not what the arcade game is supposed to be.

Were there any instances of someone making an arcade port and didn't have first-hand experience of the original?

David L. Craddock: Paul Carruthers talked to me about Mortal Kombat for the Mega Drive and SNES, but also Terminator 2. In some instances, I've spoken to people who were familiar with the game, their company would get an arcade cabinet in then wheel it into their cubicle so they could try and recreate it. Paul Carruthers, though, he was just sent a video tape of Terminator 2, the game, someone playing through all seven levels. What he focussed on - Sega wanted the Menacer gun to work, as they knew the SNES version would be compatible for the Super Scope. But if you look at his game, it's missing all these assets everywhere - he only had so long, and could only watch the video tape so many times and he just kind of missed things. He had to do a lot of it from memory - that was his first brush with porting something, and he said he felt he kind of redeemed himself when porting Mortal Kombat on the Mega Drive.

Again showing signs of my deprived childhood - I had the Game Gear version of Terminator 2, which was a light gun game on a handheld which didn't exactly work. You were just moving a cursor around. That was quite far off the mark - but it was still something I enjoyed, and they worked wonders distilling some of its essence onto a Game Gear.

David L. Craddock: I spoke to David Leitch about Space Invaders on Game Boy Colour, and Terminator 2 for Game Gear. He said he did the best he could do with it. There's only one level he was kind of embarrassed about - it's the last one, the T-1000 is in the truck ramming you, and there's a lot of flickering because he had to write more sprites than it could handle. It was an interesting one as he had to port backwards on consoles - Probe said they wanted a version for the Master System, and he had to take his Game Gear code and stretch it to fit the resolution of the Master System, but otherwise it played the same. And thankfully he didn't have to meddle with the Master System's light gun.

Nowadays, arcade perfect as a concept has kind of become extinct, partly because the arcades aren't quite like they were back then. Is there a modern analogue of the arcade port?

David L. Craddock: I think there are two analogues - this generation of consoles has brought an interesting change, for the first time we have these half-steps in the PlayStation 4 Pro and the Xbox One X. I've spoken to developers and they're not allowed to talk about this publicly - but making a game work on the Xbox One S and then X can be a real pain in the butt. There's enough differences it can be a real pain. Another analogue - there's things like Digital Eclipse's Street Fighter Collection. I didn't want to talk about just ports, I wanted to talk about preservation. Street Fighter was interesting, the emulation programmer, Daniel Filner, he said he viewed his job as more corrupting history rather than preserving it. He'd have to go into these ROMs and remove things like the Winners Don't Use Drugs screens, changing details like in Chun-Li's stage they didn't want to show the Coca Cola logo as Capcom didn't want to licence that. What Digital Eclipse is trying to do, people don't just want to play straight ports of arcade games. What they - and [Digital Eclipse head of restoration] Frank Cifaldi - focus on with these collections, like the SNK one in particular, is making a museum's worth of documents, and with things like the watch mode where you can jump in wherever. People want to play these things in a different way and learn about the history - it's like the Criterion Collection approach.

There's always this struggle developers had with porting arcade games. Developers would say, since they can't insert quarters, we don't want to give them infinite continues - do you give them finite continues? It meant some arcade ports were notoriously difficult. It's kind of like walking a tightrope - if you're not careful, playing an arcade game at home won't be as much fun as playing it in the arcade. Digital Eclipse has done a masterful job of saying here are these old games, play them the way you remember, but here's some bells and whistles that can change the context a little bit.

I'm lucky enough to have an arcade cabinet in my living room, and I picked up an original Gradius 2 board a while back. I got one of the original print run, though, and that original run of Gradius 2, there's no continues at all. Which is great, but this game I absolutely adore and I paid a fair amount for, I've never got past the third level... I'm hoping some point down the years, maybe in my dying days, I'll see the final boss.

David L. Craddock: I had a similar experience - when Ninja Turtles the arcade game came to NES, I was still a kid and my mum had this rule that I wasn't allowed to play games until after dinner, after homework was done and only for 30 minutes. So Ninja Turtles 2, the arcade game, it didn't have a password mode or battery pak saving. So every night was like groundhog day, and I'd get to the same point before my mum would come in and say I was done. And I thought I was never going to beat this game. But then I discovered the Konami code - I can't remember if it had it or a variation - and I didn't use it to cheat. I'd use it as a save system. It's another context, and another way to play.

Arcade Perfect: How Pac-Man, Mortal Kombat, and Other Coin-Op Classics Invaded the Living Room is out now.