It does get progressively harder, it just isn't as balanced as I'd like. It starts off spawning 1 "easy" 3 letter words every 3 seconds. At the 1 minute mark, it ads an additional spawner for 4-letter words every 4 seconds. Then at the 3 minute mark it starts spawning 5-6 letter words every 5 seconds. I find that once the "hard" words are spawning it's only a matter of time until I get overwhelmed.
After releasing a few game jam games that were just way too hard I've taken to always leaning towards making them easy. Especially if I don't have time for a real balance pass. After all, most players will only play a game jam game for about 5-10 minutes max, so they don't have time to get good at the game anyway.