Cognitive Screening Instruments are helpful in the early detection of cognitive changes and possible underlying dementia. These instruments test all major cognitive domains of an individual. Serious games have been investigated as an alternative approach for cognitive assessment because of their ability to motivate. Previous work mostly focused on finding out whether it is feasible to use a serious game for such purpose. We decided to investigate further how a serious game can be engaging and fun while prioritizing the cognitive assessment. In this paper, we describe the design, development, and evaluation of CogWorldTravel, a serious game that has the potential to be used for cognitive screening as it measures at least one aspect of each cognitive domain. CogWorldTravel features six game tasks that involve recognition memory, attention, working memory, language, immediate memory span, processing speed, inhibition, recognition of emotions, visuoconstructional, perceptual-motor, and planning abilities. The serious game also accommodates age-related changes and considers the gameplay preferences of older adults.