The writing in this game is excellent.
The tips are useful, and I like how the ones shown depend on what enemies are unlocked and what item is equipped. The enemy descriptions in the bestiary and the item descriptions in Rewards are well written and have a considerable degree of scientific accuracy, too. And then there's the Achievement descriptions...
But I think the gameplay itself actually isn't that great. After a while, I found myself just playing to see what the next achievement would say. I mean, sure, it's fun, but there isn't much variety. There's very little difference between the few modes that exist; except for practice mode, they are both endurance modes featuring a full assortment of enemies. The only real difference is that Nest has an end, and that hardly makes a difference to me right now as I've never lasted long enough to beat it anyways.
The mouse control is okay, but games like this make it too easy to hit a link with a stray click outside the game. Good thing Newgrounds has that "Dim lights" option.