Very snappy, I like the animations very much (they keep changing, you had fun!). I tried signing in with Google and it didn't work (blank screen). But I've played a lot with these games and I've made my own, and yours is very addictive because feels quick and the feedback is clear. Also I found the jump from the first wave (short words) to the second (very long words), a little too big. I would put an intermediate one in between.