Use of 'Like' and 'Unlike' prepositions

Question

I am confused about the usage of the words like and unlike in sentences. Like and unlike make me confused because I see them being used everywhere almost interchangeably, and to make matters worse I even saw commas making difference in meaning.

Which of the following sentences is most correct, and least ambiguous?

1. Unlike Xbox, Playstation can't play Halo.

2. Playstation can't play Halo unlike Xbox can.

3. Playstation can't play Halo, unlike Xbox can.

4. Like Xbox, Playstation can't play Halo.

5. Playstation can't play Halo like Xbox can.

6. Playstation can't play Halo, like Xbox can.

7. Playstation can't play Halo unlike Xbox.

8. Playstation can't play Halo, unlike Xbox.

9. Playstation can't play Halo like Xbox.

10. Playstation can't play Halo, like Xbox.

In case you don't know what I actually wanted to say in those sentences: I'm trying to say that Playstation can't run the Halo video game and Xbox can run that game. I probably should have tried sentences with no brands but I can't imagine any meaningful sentences at this moment which contains like/unlike.

Answer 1

Use like if you are highlighting something the two have in common. Use unlike if you are contrasting them.

In your case, you are contrasting Xbox and Playstation, so go with your first attempt (I'll ignore the pedant's objection that neither can play Halo):

1. Unlike Xbox, Playstation can't play Halo.

If you are concerned about the double negative, turn it around:

Unlike Playstation, Xbox can play Halo.

Your examples 2 and 3 have an extraneous trailing can. The phrase unlike Xbox already implies the negation of the prior can't.

Examples 5 and 6 are interesting:

5. Playstation can't play Halo like Xbox can.
6. Playstation can't play Halo, like Xbox can.

Example 6 says that Playstation cannot play Halo but Xbox can. However, example 5 implies that Playstation can play Halo, just in a different manner to Xbox. Example 5 carries the suggestion that Playstation is inferior in this comparison.

Examples 2, 3 and 7 are ungrammatical, example 8 is of similar construction to example 6, and example 9 is of similar construction to example 5.

Examples 4 and 10 each makes a direct comparison between the two, so they say that both cannot play Halo.