Me and my boyfriend made this game an year ago. Try to move all ships together and move them on attack - use A. If you attack with small number of ships, you will lose them very fast and you won't be able to finish the mission.

By the way only one player have finished all the missions and submitted score till now (except us but we made the game so it didn't count). The game is very hard especially last missions.

Instructions:
Click to select ship or shift + click to add to selection. Click and drag to select multiple ships.
Press A or Attack Button and click somewhere on the map to move there and attack any enemy along the path. Click somewhere on the map to move there without attacking. Click on enemy to attack it.
Ctrl + 1, 2, 3, 4 assigns the currently selected ships to fast selection slot 1(2, 3, 4). Press 1(2, 3, 4) to select them.
Place the mouse near the borders or use the arrow keys to move the view.

If this game is too hard for you try playing the tutorial [link]