Some questions about heaven and hell (for any believer)

[Dystopia]

---> If all sins can be repented and consequently forgiven by god, why does hell need to be eternal and not temporal? Depending on the severity of the sin, you could be tortured for a day, a week, a month, but why all eternity?

---> If no sin can be repented fully, does that mean we all risk going to hell?

---> If only some sins can be repented, how do we know which ones can and cannot?

---> Why does every sin worthy of hell always grant eternal torture? Should someone who commits an unforgivable sin start endlessly sinning (since he/she is going to hell anyway)?

---> Are Hitler and other immoral people who had faith in god enjoying paradise?

---> Are people who contributed to mankind, like scientists and artists, burning in hell because they didn't believe and committed some sins (like drug abuse)? If so, why does god punish those who help the earth?

---> If I never believed while I'm alive but repent and confess to a priest on my deathbed, can I get into heaven?

---> The former begs a more important question - Is simply believing in the divinity of Jesus and his resurrection (using Christianity just as an example) enough to get into Heaven, regardless of what I do?

---> Can I be really evil but still go to heaven if I believe and pray?

---> What is more important for getting into heaven - Good deeds according to the doctrine, or prayer?

---> Is being gay by itself enough to grant you a ticket to hell? What about premarital sex or simply having sexual thoughts about the neighbour's wife?

---> If you commit a sin while a the same time doing a good deed, which matters more? For example, if I hurt someone to make them believe (saving his/her soul to get into heaven) does the good of converting the person surpass the evil of hurting/torturing them?

---> Does god know (and distinguish?) between those who genuinely believe in him and his doctrine passed down to mankind and those who just pretend/wish to believe just to enter the kingdom of paradise?

---> To enter heaven, do important good deeds count more than small good deeds? Quantity or quality? Does god balance [mathematically] the amount of good and bad deeds (including thoughts) and determine if the overall score is positive or negative?

---> If god really values the institution of family, why doesn't he mind separating relatives between hell and heaven?

---> What the hell happens to fetuses and non-baptised children?

---> What happens to pre-Christian Humans (or pre-any religion)?

---> Isn't eternal torture a strong contradiction against god's strong love and devotion for his own creation (us)?

---> If Satan is evil, why does his house seem to have some of the coolest people on earth?

---> Finally - Do you believe if everyone goes to hell god will get bored?