Back in the spring of 2014, when episodic adventure game D4: Dark Dreams Don't Die was still months from being released into the world, its director Hidetaka "SWERY" Suehiro was dealing with the early symptoms of a condition that would not be diagnosed until more than a year later.
It began with "apathy of the mind", followed soon after by a "decrease in physical strength". He would find himself falling asleep around meal times, but ultimately tried to excuse his exhaustion away as just "terrible jetlag".
Little did SWERY know at the time that the following June he would be diagnosed with reactive hypoglycaemia, a condition where energy levels dip notably following a carbohydrate or simple sugar-rich meal. Insulin is released in response to the high amount of carbs or simple sugar, but doesn't stop being released once the meal has been digested.
Put simply, after a carbohydrate-rich meal, sufferers of reactive hypoglycaemia end up with reduced levels of glucose in their system. This can cause exhaustion, unclear thinking, headaches, double vision and an increased appetite, particularly for sweet and sugary foods.
"I finally had a five-hour-long 'sugar load test' at the hospital in June of 2015," SWERY remembers, "and that's when I was diagnosed with reactive hypoglycaemia.
"I was in poor physical health for over a year prior to then. I had been plagued by apathy of my mind, and a decrease in physical strength. Sometimes I couldn't be prevented from falling asleep after having a meal. I spent every day misunderstanding the symptoms as terrible jet lag."
D4: Dark Dreams Don't Die, developed during the time SWERY's symptoms were beginning to manifest themselves clearly, is an optionally motion-controlled episodic adventure series following the story of David Young, police narcotics officer turned private eye. He uses mementos to travel into the past, as a method of solving crimes.
Young constantly battles to prevent his stamina from dropping too low, needing to graze between meals to avoid collapsing from dangerously low energy levels. Fail to keep him topped up, and at first he'll clutch at his head, weak and unsteady on his feet. He then goes light-headed, swaying before collapsing lifelessly to the floor.
While SWERY had not yet been formally diagnosed with reactive hypoglycaemia when he was working on D4, many aspects of the game's stamina system seem to mimic aspects of living life while managing the condition, pre-diagnosis. The constant exhaustion, the use of food to stave off collapse, and Young's lack of insight into his situation all present parallels to a very real man unaware he is living with a long-term health condition.
'D4: Dark Dreams Don't Die', launch trailer
When it came to the inclusion of a food-based stamina system in D4, SWERY felt it was an important barrier to introduce players to, offering valuable insight into the realities of daily life with reduced energy.
"I've had people say to me that 'the stamina system is a stumbling block', or 'the stamina system is a hindrance'," he says, "and that's an understandable opinion to have. However, I feel that the stamina system is okay. Food as a barrier to action is valuable in the same way as money and experience is in other games. I wanted to build that real world factor into the game. That's all, simple reasoning."
It is important to note that while much of the way D4's system operates bears similarities to living life with reactive hypoglycaemia prior to diagnosis – stumbling through each day, trying to stay alert – the way stamina is presented in the game is not an accurate reflection of the way SWERY now manages his condition. Indeed, a lot of what Young does in the game would be considered inadvisable for its maker.
"Unfortunately, the stamina system isn't completely accurate to my illness. I didn't fully understand the symptoms of hypoglycaemia when I was planning out the development of the game. Also, there are differences between my symptoms and the stamina system, like the fact that I can't eat any sugar or carbs anymore because they cause my energy to dip. So I can't drink beer, even though I love beer, and drinking."
While D4 is the SWERY game that's stamina system is most easily relatable to his reactive hypoglycaemia, prior games he has worked on had similar systems and themes. 2010's Deadly Premonition, for example, featured a similar mechanic.
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The key difference between the two games is that where the former's stamina drops fast and requires constant replenishing, Deadly Premonition's falls slower, encouraging eating at more intermittent intervals. The earlier title's presentation of a human being's dependence on sustenance is a lot more standard than what's shown in D4, where small and sugary meals are frequently consumed in order to simply stay in the game. This change could be seen as reflecting the SWERY's own intensifying relationship with food.
SWERY took a break from game development in November 2015, to take personal time to manage his newly diagnosed condition. Whenever he does announce another project, I'll be watching, curious to see if its protagonist is notably avoiding sugar and carbs – not to mention beer. He's previously mentioned making a game where a girl solves crimes via the magic of masturbation – so perhaps her self-exploration adventures will be fuelled by a carbs-light diet? Only time will tell.