Why would God want to have someone killed in order to let everyone else get into heaven? Why such a brutal death? And where did the people from the Old Testament go when they died before Jesus came down to earth? How could they get into heaven? And how was there such a misunderstanding among the Jews about Jesus being their Messiah? Where did it say how they would be able to recognize Him? How could God allow so many people to go to Hell? How do we know for certain that all of these things that were written so long ago are even reliable, truthful sources?
You’ve been misinformed on several levels. God didn’t have “someone” killed so we could get into Heaven. His own Son agreed to die on our behalf because that was the only way we could be saved (Acts 4:12). The manner of His death was so brutal because our sins are so offensive and required such punishment.
People in Old Testament times who died believing that the Messiah would come to pay for their sins went to a place of comfort called Paradise to await His death so they could get into Heaven .
Jesus proved to Israel that He was their Messiah by fulfilling hundreds of prophecies about Him from their Scriptures (Matt. 11:2-5). In addition, he said after they killed Him, He would come back from the dead to prove Himself to them (Matt. 12:39-40).
They failed to see this for the same reason so many people fail to see it today. They refused to believe God’s Word, even though many believe it’s the most rigorously and comprehensively authenticated book in the history of man. And God doesn’t “allow” anyone to go to Hell. We have to choose to go there by refusing to accept His death as payment for our sins (John 3:18).
You’ve apparently taken the word of uninformed people instead of doing your own study. Asking these questions is a good beginning in your search for the truth. But you shouldn’t take my word for these answers any more than you should take theirs. Although everything I’ve said here can be verified, you should conduct your own study and satisfy yourself. Your eternal destiny depends on it.