Very repetitive and gets boring real quick. The bird feels a little heavy, but you can get used to it. Needs something to make it more interactive. Perhaps use a life system and then have certain insects that give bonuses.
It'd be fine if there was no enforced juggling. Enforced juggling as other people said just creates frustration and not strategy. It takes the fun out of tower defense games. It's sad that developers use a gimmick to create difficulty instead of doing actual balancing.
This game has serious glitch/bugs. The moving windows makes it lag so that the wrong button comes up all the time. You reach a town and then the only button available is go so you're screwed and forced to keep moving forever. Terrible.
The controls are pretty bad and it's extremely buggy on detecting double jumps, sometimes things that shouldn't be a double jumps are counted. Makes it extremely frustrating when you're not doing anything different and it says you are.