Fun game. Although there should be instructions in the game, not just on the game page. I did find the banners difficult to read, because of the colours and fonts used. Not sure if that's designed to be difficult, or accidental. I couldn't make out some of the words until they came closer.
I'd put in a few extras, like earn points to type a magic word that wipes everyone out or slows them down. Just something to break the pattern.