One thing that jumped out at me was the people being baptized were adults. Although, I was surprised to read Zwingili's criticism. Probably just goes to show that if someone is coming out of one of the state churches some of it stays with them.
I think the better distinction is when someone is baptized not how. In Scripture baptism follows belief and the clearest examples we have are immersion, but if it is done after belief and does not impart grace the method is probably not critical.
Herein is found the truth IMO.
The baptism of children, or other second hand means have always rung false to me. What makes the baptism a better circumcision is that it is done by choice, and not by mandate. The "circumcision of the heart," not done by human hands.
As to the act, I think it should be by immersion in flowing (living) water. That should be the standard, and is generally the standard of the Bible.
But I also believe that it is not efficacious. It is what happens on the inside that counts. Because of that, if water is not readily available, as in many foxhole conversions, splashes from a canteen or whatnot could replace the standard with ease. Still, the standard SHOULD be the standard.
Baptism is properly by immersion, as the word means and examples indicate, (Mt. 3:16; Acts 8:38,39) and infants cannot fulfill the stated requirements for it, of repentance and whole-hearted faith. (Acts 2:38; 8:37)
But as regards its occurrence, actually, baptism is usually synonymous with conversion, though the latter can clearly take place before the former. (Acts 10:43-47; 15:7-9)
In addition, often attempts to reconcile verses such as Acts 2:38 with salvation by grace, and to deprive advocates of baptismal regeneration from using such, en up doing damage to both faith and baptism. The prayerful reconciliation I see God showing me is that baptism is not more a “work” which appropriates justification than a “sinner’s prayer” is. Baptism is a sinner’s prayer or confession in body language, and there is no substantial difference btwn exercising one’s brain or tongue and that of his legs in confessing Jesus is Lord.
But salvific faith faith is a confessional faith, “For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.” (Romans 10:10)
God sees the heart before it is otherwise expressed, and imputed righteousness by God-given faith alone, with God working to persuade, and not by any merit of works, but not by a faith which is alone, which will not effectually confess the Lord Jesus. All of which is by grace, to the glory of God.