Adding to the Bible- eg. Inserting the name of Jehovah 237 times to the New Testament.
Adding submission to the GB/FDS to the salvation formula.
Changing the nature of Christian salvation from eternal spiritual salvation to temporary physical survival.
Denying the benefits of the gospel to 99 percent of believers.i.e., etetnal life, heavenly hope, Spirit begettal, righteousness, justification etc.
Altering the means if salvation. Denegrating faith by Adding works to the salvation formula. Denying that the blood of Christ is sufficient to cleanse from all sin.
Denying the mediatorship role of the Lord to most Christians.
The list goes on how they have changed the gospel of Christ and judged all non JW Christian's to be worthy of eternal destruction.
The list goes on.