Just downloaded it, cool stuff
If you're just re-releasing it and not building more, then maybe this is redundant, but...
Water drops - Agree they're too small. Its usable on my fullscreen monitor, but you can't see them at all on the video.
Reset - Not intuitive on how to do it. I also didn't figure out you could click the exit sign. So I started off just waiting for the countdown to finish which was a bit frustrating.
Level 2 - It requires you to immediately jump into the action to save 90% of the drops. A more graceful learning curve would introduce this pacing later in the game.
Overall, I enjoyed it. I like the idea of a sand game with an objective - I'm not sure if it's been done before or not, but this is the first place I've seen it. Thanks for sharing