Tradeoffs
Because the Java class file format incurs quite a bit of overhead, creating a complete game in 4K can be quite a challenge. As a result, contestants must choose how much of their byte budget they wish to spend on graphics, sound, and gameplay. Finding the best mix of these factors can be extremely difficult. Many new entrants believe that impressive graphics alone are enough to carry a game. However, entries with more modest graphics and focus on gameplay have regularly scored higher than such technology demonstrations.
Read more about this topic: Java 4K Game Programming Contest