I was reading this thread, and I thought asking this question again in Usage forum would make my understanding more clear.
I am briefly explaining the question here.
She plays it cool.
He plays / acts stupid.
The headlines showed you played them proudly.
Here cool and stupid are adjectives, but adverbs should be placed there in general.
My question is how to determine which adjectives can be used this way and which aren't?
Your mistake is seeking adjectives that work like this. This is barking up the wrong tree, for it is not the adjective but rather the verb that makes all the difference in these situations.
Take act as in your own example. Here you can set things up so that He’s acting slow contrasts with He’s acting slowly. In the first case, he is behaving as if he himself were a slow person. In the second, it is his acting which is moving along at a retarded pace.
But this is not somehow a function of choosing between slow or slowly, something especially important to understand given that slow can also be an adverb. It is only ever the verb that matters for these distinctions.
You have to decide whether the modifier in the predicate applies to the subject or to the verb. Comparatively speaking, only a slim minority of verbs can work this way. One oft-cited set of these is the sense verbs, such as look, sound, taste, smell, feel.
So a pig that smells good contrasts with a pig that smells well. The first pig has a good smell about him; he is pleasantly fragrant. The second pig, however, has those exceptional powers of olfaction to make him a good truffle-hunter.
So don’t look for adjectives; that’s a red herring that will lead you nowhere sound. You should be looking for verbs.
The more you will be reading the sooner you will see that the rule after a verb stands an adverb is a simplification for beginners. At first you will find now then a structure with verb + adjective as in:
Still waters run deep.
Later you will discover that the question "verb + adverb or adjective" is a difficult problem area, where even native speakers sometimes are in doubt.
I remember an example from a science fiction short story by John Wyndham, The Meteor: The meteor buried deep into the ground. The question arouse, is it "deep" or "deeply". And even native speaker had a discussion about this question.
There is no rule of thumb for such cases, only by studying such cases carefully you get a feeling when to use verb + adjective. For beginners of English I would say this is no appropriare grammar point for beginners.
