Nice tower defense game! The art was nice. Cool water shader as well. Happy to see the theme play a role in the mechanics, though the lore/reasoning felt forced. I would have liked the ability to restart a level, instead of having to reload the whole game from the beginning. Towers would sometimes shoot at already dead enemies, wasting ammo, which was frustrating for a game where the munitions are the limiting factor. More variety, upgrades, and/or combinations of signals would have been nice, too.
Well done!