If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Shoot white clouds to seed them and make it rain. Catch the rain and collect enough to fill your cup. Once your cup is full, add it to the fishbowl. When the water is hig enough the fish will help you to open the gate.
Left / Right Arrow Keys - Move.
Spacebar - Shoot.