Being that Flit is an older app made for devices that are a lot less powerful when compared to today's high end devices the app itself is very light on modern resources.

It's a very flexible keyboard that allows one handed typing without looking at the keys, Using 8 large buttons, and then a hold-and-swipe approach to determine the letter or character. 4 keys provide all 24 letters, then the remaining 4 keys provide numbers and most characters. It also allows arrow keys.