I liked it, but
The graphics are great, very good game-play, along with a pretty original theme. It is very fun to play, except for the numerous glitches. If you were to fix this game up, I'm sure you would get 4.3-4.7 for it.
I would suggest you move the up/down keys away from the tab button, as that will set the focus on the web page, and scroll the page down.
Bugs i noticed:
With missile upgrade 1, sphere enemies do not fully die, and you don't have the option to type in another word to kill them (or it just isn't displayed), the same goes for the jet fighters.
Also, many, many words do not fully display, and only the first three letters are shown for them. This leaves the player to have to guess the last letter.
In-level money changes when you hit an enemy, but does not change for the end-level summary.
I would love to see this game completely fixed up, as I did rather enjoy it.