Differences between...

[Maniak]

Are there any differences between "in" and "at" or not? And between "as" and "like"?

For exemple:

What is (more)correct?

I play game like maniac. or I play game as maniac.

I am not good in english. or I am not good at english.

[clevercells]

Well,the role of "In" and "At" is most of the time interchangeable so it's not easy to distinguish the difference between them but in your second sentence.
the standard form is : I am good at english.

However,in this sentence to be good in seems to be more likely than to be good at,like : He is the best one in the class in English, but in Latin and biology he is not good. Simply because there isn't an easy rule to know when exactly to use one and not the other.
Also we use "At" to talk about a specific place like saying : I am at the Candy Store, I am at the post office, I am at the bus station.

We use "In" to talk about a place that is enclosed or within boundaries like : I am in the city, the coin is in the box, the Car is in the park etc.

Now for "Like" and "As", "Like" is followed by a noun or pronoun,for example : I am like a lion or Like a lion I have a brave heart.
"As" is followed by a subject + verb, for example Garry Kasparov Is a good chess player as Emanuel Lasker was before him. so here I'm not sure if you can say I play game as a maniac, but I play game like a maniac is standard.

I hope my post can help but still you can search more for further information.

N.B : not a teacher.

[Tdol]

Speaking like a lawyer = speaking in a way similar to the way lawyers talk. It doesn't mea that the person is lawyer.
Speaking as a lawyer = the person is a laywer and is giving a professional opinion
So, if you play games like a maniac, you play games in a wild, exuberant manner. It doesn't mean you are a maniac all the time. If you were to play games as a maniac, you are a maniac and are playing games in your capacity as a maniac, which doesn't make much sense.

[Maniak]

I understand it, I think. Thank you.