They are simple present tense. They are examples that basic tense.
I play games now.
... is a very basic sentence. May be too basic and simple to be used in real life situations. No one says it like that in real life.
I want a chocolate now.
... is also very basic. You may hear something like that in real life but saying it like that sounds like you're ordering someone to get you chocolate quite rudely.
They're grammatically correct but we usually don't say it like that. Instead, depending on the situation, we may say one of the following:
We're playing games now.
We'll be playing games now.
I'd like some chocolate.