I would add a couple, I would go to place a tower and it was all green. I click the mouse and suddenly the tower moves and its red and of course nothing builds. This happened to me enough in the three games I played to be annoying.
I'm not sure I noticed a difference in click sound between one that worked and the tower built, and one that failed because it suddenly turned red.
Admittedly my graphics board is not top of the line, or new, but I found scrolling to be painfully slow. Maybe there is a way to tune that I haven't looked for.
Not sure I found the slow down, speed up options TheZone mentioned.
There are areas in the first two maps where it is impossible to hit the enemy ships. Specifically around the bases. If the ships get past everything in the maze, they go and hide behind the base. As you cannot build anything behind the base you are pretty much out of luck once they get back there. The base does what it can but it becomes a ticking clock to doom especially on the first map.
The second map I unlock "grenade launchers" and my placing them on the hill to the right of the base they just about reached the far side of the base as the longest range weapon I had. As the enemy ships float in and out, the grenades helped, it just took a long time. It was pretty close, and sadly I was playing easy.
It's early days of course but I'm wondering what sets this apart from any other defender style game especially in the mobile space like Balloons TD 5. Different graphics, different weapons, same premise. I'm looking to forward to seeing how this develops.
Cheers,