Its just an opinion. Most people I know who have read the book liked it too.
I don't really care if you don't take my opinion seriously. As such, feel free to stop reading this at this point. Hopefully others who may like the story will take your opinion with a grain of salt.
I agree that a lot of the science is not well explained, but with science fiction I always must suspend disbelief. I like Star Trek too, but c'mon - travelling through wormholes and time? Not really likely and also not the point.
It's been a while, but I thought he was asleep when the hydrogen mix went way up. He noticed immediately when he woke up.
Please explain what's wrong with the stoichiometry. Hydrazine is N2H4. React O2 and you get two H2O and one N2. I agree that getting this desired reaction safely may not be well explained.
The potatoes were genetically engineered and he had bright lights. I agree that its unlikely, but it is at least plausible.
In any case, like any book, some like it and some may not. I recommend you skip the movie - I think I'll like it.