This game was made by a team of doctors. Having to figure out what medical procedure to use for a given affliction is a big part of the challenge. It's difficult because it's meant to be highly realistic - if you were stranded on an alien world, you wouldn't fare much better!
That said, it isn't a perfect game by any stretch. I can see where you're coming from with the lack of information on what kills you, it can be very frustrating. Still, I think that if you can see past the flaws you'll find it's a good game with some fun to be had.