Test your memorization and fast touch skills in order to form the word by touching the letters within time. Touch an invalid letter, or let the timer expire and the level fails. As you progress on the levels the word count will increase and the letters will disappear faster. Letter count starts from 4(very easy) to 14(hard).
The order by which you touch the letters don't need to be the same as the order of the letters in the word.
Play store link:
https://play.google.com/store/apps/details?id=fousteris.formtheword