Yes basically your correct....thats the islamic perspective on that issue.
Guys I am a muslim and you are getting confused about islamic issues. If you want to study islam you have to study it with a broadmind, patience and not be biased. I will try my best to clear few issues especially with regards to heaven and hell.
In islam first of all no one is guaranteed heaven and nor does every one go in hellfire either. Prophet Muhammed himself has said in one of his sayings (hadith) that 'I am a prophet of Allah(God) but even I don't know what my end will be' or something to this effect. I can't remember the hadith number but it is there. So this shows even the founder of islam is not guaranteed paradise let alone average muslim. It is very interesting to note that this issue differs so much from christianity where if you believe in jesus and take him as your saviour you are instantly saved but this is not so in islam.
From islamic perspective life is a test from God (Allah) and also a means to discover Him. God has stated in islam that this life is a very short one and everyone will be brought back to Him. He already knows the past, present and future as all of this is his creation. The time is also his creation. Yet He is unlike any of his creation and beyond time.
He has also stated in Quran that it is HE who created good and evil so that he may test us through different circumstances. Also sometimes people say that earthquakes struck poor people; if God was so loving and caring why did He let it happen. Well in islam God has already appointed a period of time in which certain events will occur and in which He has also given humans free will to exercise with in those events which can never be delayed nor postponed based on his perfect knowledge which we can't have access to.
In Quran God states that when time of death comes it can never be delayed or postponed. Also He says in Quran that He will not be questioned as to what He does but they will be (the people).
You have to realize from islamic perspective God does what He wills. It is not a question of ascribing good or evil to God. In islam God is One in Absolute form without any partner just like Judaism. In islam God is mentioned through His attributes like loving, compassionate, just , powerfull, omnipotent, all knowing etc. These are His attributes by which we describe Him.
But on a truly divine level it is His 'Divine Essence' which remains the greatest mystery, i.e His Self which is the True meaning of God. Countless mystics of islam who were greatest during their time have tried to know the exact understanding of God but have only got reflection of God's atrtributes. Among some islamic scholars it is known that to try to understand God's Divine Essence would only lead to confusion, stray from islamic path and could lead to doom. Thats why no one dares question Divine Essence.
Coming back to the question of heaven and hell. In islam there is a judgement day where every one will be judged individually with no links to family, friens, relatives. So whether you are muslim, christian, atheist etc; each one will have a case with God and then only God decides who is going where. For instance a very pious muslim can still be thrown in hell whereas a non practising muslim can go to heaven. Also there is a reward in the grave aswell as there is punishment in grave.
Also about people being muslims, christians, jews, hindus, buddhists etc; God has stated in Quran that 'if He had willed He would have created you as one nation but there will always be differences among them' or something like this. Just reiterating earlier Quranic quote that 'He will not be asked as to what He does but they will be'. So it remains mystery why people were created in nations, tribes, religions etc. I guess you have to ask God directly about that.
Guys I just touched on some basics of Islam. Obviously to study islam to the greatest depth would require immense time, dedication and lots of books
. But I will say this; if you want an appreciation of islam read the Quran along with sayings of :
-Prophet Muhammed
-Ali ibn Talib (Cousin of Prophet muhammed and 2nd most important islamic figure after Prophet Muhammed)
-Abdul Qadir Jilani (One of the greatest islamic mystics of all time)
Ali ibn Talib is especially known for his wise sayings about life and other issues.
I hope I have clarified few issues and hope you can also appreciate Islam better