Scored 2985 before misreading one letter as another, which seems more like a game font than player problem; it could stand to use a more serif font for the letters.

Anyway, it just seems like a proof-of-concept and not really a game, so I just can't rate it highly in its current state because:

1. There are no levels; it's just one scenario with no end or pauses/way to take a break. You can't even go to the bathroom while playing it without starting over.
2. The difficulty didn't seem to increase, as it seems to hit a wall after 1000 points or so and it never became overwhelming, which made it become boring.
3. The plant's shield and rotating cube and art basically mean nothing because they aren't used in any way; the entire gameplay is just in looking at the letters, which are hard to see because they barely turn red with no other visual effect when pressed or waiting. Plus, the letters aren't even arranged as left hand-versus-right hand, so the layout is confusing.

It could really stand to use health, power-ups, and/or levels with different goals or something, instead of just one simple, sudden-death/1-HP arcade scenario. The ability to pause, maybe see different sides of cubes, see more enemy shots than just lasers (like missiles that would send a word or something) would make this far more interesting.