Alpha seeks to present basic unchanging Christian doctrine, but in a package, which is acceptable to people today. It is the presentation that is new, not the doctrine. The friendly, informal approach shows a respect for where people are at. Watching a video is something which people are comfortable with. The simple but enjoyable meals are part of Alpha's success.
Alpha is run by the local parish and works through relationships.
It is a form of evangelism that does not require big name speakers or the booking of football stadiums. People come on Alpha because their friends and relatives invite them. Then they invite their friends and relatives. When people on Alpha they find themselves among the people who are the local church. Through Alpha it is the local parish community which is opening its doors in an unthreatening way.