Knowing the letters is not reading. These four games are the step after that: what a word means, what it sounds like, and what a sentence is telling you.
Rhyme is not decoration
Hearing that "cat" and "hat" end the same is phonological awareness, and it is one of the strongest predictors of how easily a child will learn to read. It is a listening skill, not a spelling one, which is why the game says every word aloud.
Comprehension, not speed
There is no timer and no words-per-minute. A child who reads the sentence twice and answers correctly has done the thing the game is for.