Do you believe in Jesus? How do Krishna devotees view Christianity? Is there a concept of hell in Krishna consciousness?
We accept Christ as the Son of God, as God's empowered representative on earth, but not as the sole representative who has ever come or will ever come. The Supreme Person visits this world in many ways. Sometimes God sends His son, like Christ, but sometimes He comes Himself, as Krishna or Rama.
We accept Jesus' statements that he is the Son of God because he was representing God by engaging people in worshiping God. In the Bhagavad-gita, Krishna also promotes the worship of the Supreme Lord. Jesus did make a distinction between himself and God the Father. We accept that Jesus and God are two distinct personalities, but because Jesus was acting purely in the interests of God the Father, they are one in spirit.
It's important to understand that there is only one Supreme Being, and that He is so inconceivably great that He is seen and known from many, many different angles of vision and described in different scriptures in different ways. We have the greatest respect for any teachings that bring one closer to a clear understanding and knowledge of the Supreme Person, with the goal of developing a mood of loving service to Him.
Vedic literature provides extensive descriptions of various types of hellish environments which are designed to reform the conditioned living entities' tendency to exploit the material world unrestrictedly. More information on that in the Fifth Canto of the Srimad-Bhagavatam. Hell exists, but it's not eternal. For a limited number of sinful acts, a limited length of time in hell is given. Then one gets another life to try again.
If you have faith in Christ, do you think he would say that you would go to hell? We also disapprove of idol worship. We make very clear distinctions between idol worship and Deity worship. When one imagines a form of God and worships that according to his imagination, that is 'idol' worship. When God says in scripture that if you make a form of Me using these substances and worship according to these directions, I will reveal Myself to you through the medium of the Deity. That is Deity worship.
Srila Prabhupada explains that Deity worship is authorized by God while idol worship is not. He uses the analogy of the mailbox. If you put mail in a U.S. Postal Service mailbox it will go to the destination. If you make your own box, and paint it red and blue and write 'U.S. Mail" on it, the letter won't go anywhere, because the box is not authorized by the postal service.
Catholics generally have fewer problems with the concept of deity worship than Protestants since in that tradition the form of Christ and those of the different saints are seen as spiritual and worshipable. Some Catholics are surprised by the similarities in the traditions. The Eastern Orthodox Church is also similar but they call their worshipable forms "Icons" rather than deities. In Sanskrit such forms are called ‘murtis’.
It could be argued that the Ark of the Covenant—which carried the Ten Commandments, Aaron’s staff, and holy manna, and was protected by angels—was also spiritual and therefore worshipable, like a deity. We consider scripture to be as worshipable as God.