Fun and ingenious - the only 1-bit-input game I know of other than Fishing Girl - but the ending (?) is a bit annoying - the objective is supposed to be "survive all the waves" but the "Final Wave" seems to just repeat over and over again indefinitely. Valid design choice, but be up-front about it.
Also I got through the whole (?) thing without ever realizing that the floating light was supposed to be picked up. I thought it was a hint as to the direction of the next fish or something.