Sentence Correction

I'm working through the MGMAT SC study guide and took a mid chapter quiz, the answer to question 3 is not very clear to me.

The sentence to be corrected is

"The proliferation of computer games designed to involve many players at once were first developed before the widespread availability of high-speed internet connections"

The solution says "the proliferation...were first developed is illogical" and should be the "computer games were developed"

It doesn't state whether I need to get rid of the word proliferation or what the complete corrected sentence should be.

From my point of view, the word first is a redundant time reference with before. Before seems to hold the sentence together so I just said to get rid of "first" and it would be correct.

But the solution statements makes it sound like it should be "Computer games were developed before the widespread availability of the high-speed internet connections"

However, this puzzles me because this new sentence has changed the meaning of the original sentence (it's excluding the many players)

Any help is appreciated...

Let's just be real here. This sentence is seeking to say two things at once and is not doing a very good job of it. It starts off talking about the proliferation of computer games designed to involve many players at once, and then shifts course to start talking about the games' being developed. So as the sentence stands there is no meaning. So fixing it will necessarily involve changing the meaning, from no meaning to some meaning.

So my response is to choose one or the other of the two directions the sentence is headed, creating these two possible constructions.

The proliferation of computer games designed to involve many players at once began before the widespread availability of high-speed internet connections.

That construction makes The proliferation the subject.

Computer games designed to involve many players at once were first developed before the widespread availability of high-speed internet connections.

In this one Computer games designed... is the subject. and so were...developed works as the verb. The use of first is ok, and not redundant, because rather than conveying that the games were all developed before the widespread availability of high-speed internet connections, the sentence is saying that such games have been developed over time and that they were first developed before the widespread availability of high-speed internet connections.