Careful passing that Didache on... It makes plain that what St. Paul was describing as a "prayer meeting" is pretty similar to Catholicism. In fact, if anything, the Catholic Church has gone all soft and mushy in the last 2,000 years. Confession, abstaining on Fridays (AND Wednesdays), fasting before Eucharist: all those Catholic "inventions" are all there.
Frankly, it also might be useful for how to properly do a charismatic mass...
And to be fair, a partial score for the Protestants: The earliest bible to include the verse, "For thine is the kingdom, and the power and the glory, now and forever," is from the ninth century. While the Didache does not contain this in the entirety, it does include a substantial portion, "For thine is the power and the glory" after the Our Father.
(The Catholic church does not include this at the end of every recitation of the "Our Father," (Lord's Prayer); it is considered a pious addition, but nonetheless an addition to sacred scripture.)