Yes, i've also gotten to hard mode lvl 5 but that last boss kept killing me. I think you had to type 2 parallel letters per tick on that one...
I've noticed a bug/typo... Let's say you started playing on easy so when you beat it you'll go to normal mode and when you beat that you'll go to hard mode. But the porblem is that when you're in normal and hard mode and you just cleared a stage, the screen will still show that it's on easy difficulty. Unless easy mode gets more and more difficult, i doubt this is normal.
Also, I was wondering why this program requires so much ram out of your system? When i run it it takes like 50% of cpu to run it....