Jazz Jackrabbit | DOS game online

Jazz Jackrabbit online DOS game is an arcade side-scrolling platform game, that is single-player and it is part of its homonymous franchise. The game is set in a fantasy world based on the Greek story "The Tortoise and the Hare", in which the rivalry between the two species, hares and turtles, is still going on after thousands of years. The player has to assume the role of Jazz Jackrabbit, an anthropomorphic green rabbit, that has to destroy the villain, Devan Shell and save the Princess of Carrotus, Eva Earlong, to restore the peace in all worlds. The gameplay is divided in six levels, which are set in three different worlds. At the end of each one, there is a final boss that the player needs to defeat, in order to gain more points and go on to the next level.

Wikipedia: https://en.wikipedia.org/wiki/Jazz_Jackrabbit