It's a pretty good game for just $1 lots of hours of playtime.
You do get an upgraded Turret and/or platform for each new world, it doesn't carry over but at least you are not starting from scratch every time.
It would be nice to have a high score though, hopefully in the next update...
Ditto this! I really enjoyed the game but when I heard that, due to some last minute changes in the final build, no score recording was included in this first release, it really dropped a few stars in my ranking.