Draconus is a platform game developed by Cognito in 1988.
The hero wants to reclaim back his kingdom from the Tyrant beast. In doing so he runs or jumps through various screens, in which he encounters on bats, balls or giant rats. These may be eliminated permanently by a punch or fire breathing. The fire breathing is limited, but may be replenished once in a while by collectible symbols. As superior task, the hero must find four special abilities and then face the final battle. One of the abilities allows him to metamorphose through special platforms into a water being granting him access to further areas.
Source: Wikipedia, "Draconus", available under the CC-BY-SA License.