How do Islamic perceptions of heaven and hell differ from those of Christianity?
This is a difficult question to answer, because theologians are constantly arguing with each other about views on heaven and hell. So, there is little consensus even among theologians of each religion. In light of this, I will limit myself to general points.
From a traditional point of view, both Christianity and Islam believe in heaven and hell. Christianity says that heaven is a place where there is no sorrow, no pain and blessedness. There will be a new heaven and a new earth and God will be there and this will be the cause of joy. At times, heaven is portrayed as a wedding feast and at other time heaven is portrayed as paradise or a renovated garden of fellowship.
In Islam heaven or paradise (firdaws) is a place of physical and spiritual pleasure, mansions, feasting and interestingly virgin companions. From this description, it is similar to Christianity apart from the virgin companions.
Hell within Christianity is described as outer darkness, the place of gnashing of teeth, and a fiery lake. These are some of the most common descriptions. However, it must be stated that hell is not mentioned too much in Bible, even though it is definitely there.
Hell, or Jahannam in Islam is mentioned frequently and it is seen as a place of fire and various levels. The deepest level has a boiling cauldron and it is reserved for the worst transgressors.
The difference between Christianity and Islam when it comes to hell is chiefly the various levels that Islam has. In the end, what really differs between Christianity and Islam is how one gets into heaven and hell.
Just as the perception of god is different between the two faiths, so is the perception of heaven and hell. For example in Christianity, the concept of salvation exists. salvation in Christianity is defined as deliverance from sin and it's consequences, brought by belief in Jesus Christ and his sacrifice. Because of salvation, many Christians have the belief that faith in Jesus Christ alone is enough to get into heaven.
Islam, on the other hand, does not teach that faith in god alone is enough to secure heaven. Instead, muslims belief that both faith and good actions allow one into heaven. In Islam there is no guarantee that you will get into heaven just because you are Muslim.
The main difference between Islams perception and Christianitys perception of heaven hell is how one gets in, not so much what type of place each one is. Both faiths wholeheartedly agree that heaven is a place of bliss, and hell is a place of great despair.