By freeing ourselves from conventions, we see things more clearly.
By freeing ourselves from confinement we embrace freedom.
Do both of these require the comma. Do these form complete sentences? Why?
Heard this stunt left the man barely alive.
Never liked it when the girl dies at the end of the movie.
Neither of the first two propositions requires a comma. Each begins with an adverbial phrase, which modifies the main verb.
Both are complete sentences: each has a subject and a transitive main verb with an object.
The second two will do for informal talk, tweets, messages and emails. It is obvious what the subject is or would be. Writers of drama and fiction or poetry might use this informal mode for literary purposes. But in formal writing the subject cannot be omitted.
