[caldrail]

Officially the effects of hypoxia begin from 8,000 feet above sea level, though in fairness, you'd hardly notice it at that height. From around 12,000 feet the effects become more pronounced becoming gradually worse as height increases.

why not also simulate peoples guts busting because of high pressure and intestinal gas... no joke, quite a few pilots died because of this i was surprised myself

Pardon me? Intestinal gas under pressure does not cause catastrophic explosions of the human gut. It would cause a colossal fart and a lot of discomfort. In order for this to have an explosive effect, the change in pressure would have to be extraordinarily quick and extreme. As yet, changes of altitude of this order are not possible even in fast jets, and in any case, it would be your ears that suffer more damage. Could you tell us where you got this gem? In all the aero-medical texts I've read, nothing like this was even suggested.