The gameplay in Eternum is simple: you have to go through each level and grab the treasures while trying to survive the hundreds of traps and enemies that appear. The only two weapons you have is the ability to jump (a must in any self-respecting platformer) and attack (which you use to get rid of almost any enemy). The game has a total of 25 levels, including some special levels with their corresponding 'bosses.' As you go through the levels, new elements are introduced into the game: new enemies, new traps, power-ups, etc.
Eternum is a great 2D platformer that maintains the feeling of the arcade games from the 80s thanks to its delightful graphics and an appropriate soundtrack for the style.