Proving that my vocab is not as expansive as I would like, I did manage to attain the dizzying heights of 40 (several times) and in the process was responsible for donating 1,340 grains of rice. It goes without saying that serious word people, were comfortably in the 40s and regularly attaining a score of 50.
Update: with a bit of practice you can improve. Some words repeat but not enough to explain the improvement. I’m now scoring primarily in the early 40s and briefly made it to 44.
snail 
How awesome is this. I played (and got about 10 right) then this girl I work with was amazing! All together we donated 1290 grains of rice and she got up to 43 (she tried to beat your 44 but no luck!)
It’s ok, my girlfriend is way ahead of me, she got the maximum score of 50 :) This is so, so addictive.
I have a question about this game: Does it actually have a conclusion? I played for about forty minutes last night, and there was no end in sight. I hit a score of 45 before missing any, but then bounced around the low forties a long time before stopping when I reached 45 again. Is that the way it works, or will I reach a point where the screen says ‘Game Over’?
There is no end. The highest “score” is a vocab level of 50. It takes three correct in a row to go up a level and one wrong to go down a level. Every time you get a word right, you’re responsible for 10 grains of rice being donated to the UN World Food Programme. I, and some of my friends, have spent many an hour on this :-)