Serious games are generally considered to induce positive effects in the areas of learning motivation and learning gains. Yet few studies have examined how these factors are related. Therefore, an empirical study was conducted to test the relationship between anticipated enjoyment and willingness to play, as well as between game enjoyment, self-reported cognitive and motivational learning gains and test results. In an explorative study, 74 children from five primary schools played the learning game AWWWARE. The results of pre- and post-tests were analysed using multiple linear regressions. The analysis showed that anticipated enjoyment played only a minor part in students' willingness to learn with serious games. Of greater importance was the students' expectation that the learning game would be easy and instructive. The level of actual enjoyment of the game also had a smaller influence than expected. While there was a correlation between enjoyment and the motivation to continue being engaged with the subject matter of the game, no effect was found with respect to self-assessed or tested learning gains. The results lead to the conclusion that other factors, such as explicit learning tasks, instruction and support inherent in the game or supplemented by teachers, may be more decisive than the experience of fun during the game.