Deaths start to pile up when hospitals can't accept more people which otherwise would have recovered. A rapid transmission rate was bad, but hospital saturation was the real COVID killer.
While the figure for deaths isn't that high, not sure if the modelling of 'do nothing' would include the extra covid deaths due to overwhelmed hospitals?
[one of the co-authors of the game here]
What you got is CFR 4%, which is highly plausible. As in reality, what you see as cases, are just confirmed cases.
IFR could be calculated only from the explanation only at the final screen, where the actual number of infections is estimated (it's several times higher than the confirmed cases)
We could legitimately say that in your game, the number of infected people was not 2.1M, but, including reinfections, there were up to 6.2M infections, according to experts’ theories. The game and your results only register the officially recorded infections (based on test data).
Early into the pandemic last year I did a rough calculation multiplying out the death rate per age group by the US population by age and I recall it was something roughly around 5% so a number of 4% doesn't seem too far off. Granted the big assumption was infection rate and hospital capacity remained the same (eg New York was at 0% but other states were not).
Taking in data present today and looking at countries that are doing nothing (Sweden), their total population death rate isn't as high as 4% either.
Infection fatality rate for COVID in the Western world in practice was under 1%. I am quite skeptical of the idea that overwhelmed hospitals would quarduple that.
Keep in mind I originally did this exercise back in the early days of the pandemic with limited data. I can't locate all the original page I used but these new numbers work out. Going by previous estimations if everyone in the US got infected theoretical death is 1.9% of the population [1]. In march 37.7%[2] of hospital visits required the ICU and 13.6%[2] of hospitalizations resulted in deaths. So here we make the big assumption that everyone who died of COVID did so in the hospital which means 14.6% of COVID cases require the hospital. The next assumption is that if you don't have access to an ICU with COVID-19 you're going to die. We can increase "hospital" capacity with beds in stadiums and schools and such but we won't have enough equipment for more ICUs, so assumed ICU rate multiplied by assumed hospitialization rate is the worst case deathrate of everyone getting infected in the US at once in the early days of the pandemic, which is 37.7% * 14.6* = 5.4%
I'm not fooling myself with precision so I concluded roughly 5%.
An interesting note after the fact that the early estimated US deathrate of 1.9% tracks modern data pretty well [2] which is 1.8% (605,792/33,769,600).