Enemy killed me when we were separated by rock. Flying above the top of the screen makes it very hard to kill them when on top. It much harder than original. But sounds are nice, responsive controls. This is going to be nice after a couple of tweaks.
Good start, nice graphics.
The bullets that you shoot are red, and the background and ship and other things are red. Perhaps a different color? And not simply a slim needle, but a little comet perhaps?
This is a fun TD. Get the EMP in place and you will have it perfect.
The triple speed is defective. I've tested it and weapons are not killing tanks at triple that they did in normal. Saw and Bomb most notably.