Well since Cody looks like a pigeon, I assume he is a pigeon. What do pigeons do for fun? Drop their load on innocent peoples’ heads and clothes, for one. But that may turn out a bit nasty for a fun game. Pigeons also like to eat bread crumbs thrown at them. So maybe you can depict Cody walking around, desperately looking for some crumbs. Words are flying across the screen and when typed in completely, the words ‘explode’ into bread crumbs falling on the ground. The longer or more difficult the word, or the faster the word was typed, the more crumbs it will generate. This will partially regenerate Cody’s health bar. Increasing levels will cause the health bar to deplete sooner and faster typing is required to keep Cody alive. If you take that as the basis for the game, you can think of plenty off ‘add-ons’ like bonus words that regenerate Cody’s health completely, or bogus words that will cause his health to further deplete.
You can make the game increasingly more difficult by choosing more difficult words and/or let them pass faster.
Just my random thoughts here... what do you think?