A player can easily top 100,000 or more on this game using two basic tactics: maximizing the points available, and ensuring the cannon is always best placed to destroy any balloon that grabs the king. Since all cannons are expendable, success often depends on their deliberate tactical destruction.
Keep an eye out for the giant balloon. These balloons are worth more point than regular balloons. Shooting it once makes it become a medium-sized balloon, and shooting it a second time reverts it back to being a normal balloon.
Giant balloons never appear by themselves - there will always be at least one small balloon on the screen at the same time. As soon as you see a giant balloon start to form, let a normal balloon destroy your cannon as soon as possible. This should give you enough grace time when you reappear to fire three shots at the giant balloon for 3000 points, and then position yourself correctly if there is a balloon attempting to abduct the king. It is possible to destroy 5 or 6 giant balloons by per level, gaining you around 20,000 points.
Try to keep the level going as long as possible unless you're down to your last 6 balloons - at this point giant balloons rarely from.
Just like Galaxian, the game only goes up to round 48. If round 48 is completed, the game will continue to work but will always report the level as 48.