Neptune's blessing makes seagulls possibly the best bird. Not being able to die over water is a huge bonus, especially when a plane can come in from the side and kill most of the flock without warning. I often end up with a flock exclusively of seagulls because they just survive so much longer. Also, having an achievement for not getting other birds to join the flock is annoying if you increase the song range, and refunding adaptations to get it is annoying if you have a fair number of them.
It would be nice if the game could record how many slices it takes you. So if you're in 3 slice more and do a level with 2 slices, you don't need to redo it later.
@JoeMcBobski: Actually, mass does affect terminal velocity. Though I doubt that's the explanation in this game, games don't need to follow scientific laws. Why would they?
The starting platform in level 3 is way too small. 4 times in a row now I'm forced to fall off because no enemies get close enough or drop bombs, and there's no time to build up the boost bar.
For those of you complaining about the level 3 boss - just use a fireball right at the beginning (or put a tower so it shoots right when he enters). Then put towers towards your gems. If you have fear turrets it can help, because they can give you extra time (since the enemy runs away). Or, you can just play a few more levels, and level up a few times, and then do level 3 more easily.
Along with the other energy issues (needing wind power with perpetual motion machines) apparently the gears themselves require light to exist. If you remove it, gears in dark areas just disappear.