Quite a unique word list you have for this. Both times I played I'm pretty sure it gave me words I've never seen before.
It felt to me like if I didn't hit the wrong keys a couple times that I could just keep playing practically endlessly - but maybe the timer speeds up over time?
Personally, I'd ditch the lives mechanic and give a time penalty when the player mistypes. And then if you gradually decrease how much time the player is given or gradually make the words longer, you'll have a bit more of a difficulty curve to give the player a sense of progression - compared to right now where you might get a 12 letter word and then a bunch of 4 letter words in a row just by random chance. Could also have a fixed timer replenish a few seconds for every completed word. Lots of options to spice it up I think.