If you see a red arrow, do the opposite: ignore the direction of the arrow and follow the word.
Swiping correctly gets you additional time. Swiping incorrectly - your time will be penalized.
I played MindArrow once and got a score of 348. Only 31 players are on the Game Center Leaderboard. I'm #10 at the moment.
I found MindArrow a bit too slow. But I still like the concept and think that we should all try these games out once in a while as a change of pace.