This is a Stroop test. A colour word appears in large letters, but the colour the letters are painted in is chosen separately from the word, so the two usually disagree. The instruction line says which of the two the round is asking about, and you answer with one of four coloured buttons before the timer bar empties.
A correct answer is worth 10 points plus 2 for every answer already in your streak, so the second in a row gives 12 and the third 14. A wrong answer, or letting the eight second timer run out, resets the streak but never subtracts points. Best tracks your highest score. There is no game over: the next question arrives about a second later and the run continues until you leave.
No. You keep your score and only the streak resets. The next question follows automatically.
The round counts as a miss, the correct answer is shown in the message line, and your streak resets.
Yes. On a touch screen the game shows on-screen buttons, and games played with a mouse work by tapping.