This was great,

A few notes:

• I actually really like the core mechanic. It's punishing enough if you "mess up" and don't type in the enemy fast enough, but with just enough forgiveness to help you recover from your mistake.
• I really want more enemy variety - perhaps stronger enemies are phrases or compound words, and smaller enemies could be as big as a single letter.
• I never felt "out of control" with the switching. Meaning: switching always followed the same pattern. Perhaps randomizing which one is chosen next would add a bit more challenge while adhering to the theme a bit better.
• I'd love to see powerups, as well. Things that clear the screen, keep you on a single enemy, or eliminate more than one letter.
• I like the endless mode, but I'd also like to see a "campaign"

Thanks for letting me play your game