"so as it be a German play, no matter what, with a good tricking, shifting after-piece, and a figure-dance, and a hornpipe"
19th century sheet music for a hornpipe
Public Domain19th century sheet music for a hornpipe - Credit: Oliver Ditson

 Like the play on which Lovers' Vows was based, German plays presumably had a certain reputation, possibly a risqué one?

An archaic meaning of trick is to decorate or adorn in an extravagant way.

A figure-dance is one which consists of several distinct divisions, or figures.

A hornpipe is a lively dance (associated with sailors and often performed by one person only) as well as the name given to the music for such a dance. A hornpipe is also a type of musical instrument, although it is the dance that is being referred to here.

Listen to two hornpipes from Handel's Water Music here and here.