I had the same experience ~ 700 pts. with a week or two of playtime. Hadn't really played much TH before so I enjoyed the game mechanics (the plot line's none too engaging). I wasn't sorry I bought it for $10 a year and a half ago, so it's probably still worth $6.
[quote name='SlammedNiss']I got 700/1000 achievements for this game. Took me about 2-3 weeks of casual playing. If you've played the other Hawk games, this one is about the same when it comes to difficulty. I just picked up Project 8, and that's quite a bit harder so far.[/quote]