If the criteria of getting in to heaven is just belief in Christianity, then this to me seems incredibly injust.
So heaven is full of people who happened to luck out on the right religion and believed it, regardless of whether they investigated it or not?
I wouldn't want to praise a God that made such an injust, screwed up system, knowing full well good people who were either skeptical or just born in the wrong country would be discriminated against for eternity. That isn't a love of people in my book and not a God worthy of any kind of affection.
Let me respond to some of this from my perspective...
The criteria for admittance is NOT belief in Christianity - it is by having belief in Jesus Christ...these are very different things.
Jesus Christ tells us clearly the requirements of getting into heaven (particularly in Johns gospel). If you believe the gospel accounts, you will believe Jesus lived a blameless life, performed an array of miracles and was then resurrected from the dead to ascend in heaven. For me, these credentials provide authenticity to His claims re. heaven, hell etc...
We are all presented with the same evidence - you can read the account of Jesus Christ just the same as I can. You can look at the world around you and make your mind up re. Gods existence just like me. You can look at other religions just like I can. Who else lived a perfect live, performed miracles AND rose from the dead? This deserves our attention! Jesus Christ made it clear that ONLY faith in Him would save mankind. Do you believe Him or not? If you do, its not "lucking out"-its a decision based on a conviction that Jesus was who He claimed to be. If you reject His claims, you cannot accuse Jesus of not being clear in His warnings of the consequences - He made everything very clear...
My point is that it is a choice. I have decided to follow the teachings of Jesus Christ. Up to now, I presume you haven't. If it turns out that I was wise to follow Christ and I go to heaven, how is this unfair on you?! You saw the same evidence as me. You can read His claims re. salvation and learn about His life any time you like! If you choose for whatever reason that you will not accept Jesus' message, how can you then complain if it turns out to be true? Many millions of people have been convinced with the same evidence...it is not an injustice to those who reject the message - it will prove to be a bad decision...
Re. those from other countries who have never heard the message:
Faith in Jesus Christ is on the increase far more in countries like Iran, China and many Middle East countries were the gospel is banned. You will never hear about this on BBC news but if interested an internet search on subject will probably help. Suffice to say, where the message of Christ is banned, Muslims are having visions/dreams etc resulting in them giving their lives to Christ which always leads to persecution and many cases, death. This will sound like a very strange phenomena to you, but I believe God will always reach people who want to be reached...
Whatever you may feel about the injustice of those who never hear of Christ, the important point for you is that YOU have heard about Christ and can read about His life whenever you like. If you choose to reject Him, surely you can't blame anyone except yourself if it proves to be a mistake?