Don't need to cancel operations
On second thought, increase the drag a little bit (thinking below)

I thought about it some more last night, and I realized that I disagree
with the notion that the controls should be extremely responsive. In
fact, you are under water: part of the strategy is adjusting to the
inherent drag. Moreover, all of the other incredibly fun and successful
games with similar gameplay have a degree of drag which is comparable to
that expressed here: Doodle Jump, Ridiculous Fishing, etc.