Commander Keen 5 online DOS game The Armageddon Machine is one of a series of single-player side-scrolling platform video games. The series follows the eponymous Commander Keen, the secret identity of the eight-year-old genius Billy Blaze, as he defends the Earth and the galaxy from alien threats. The levels are full of robots and many other threats that he needs to destroy, plus many dangerous traps. If the protagonist gets touched by a villain or a robot or falls into one of the traps on his quest, he can lose one of its lives. However, he has some weapons with himself, like his raygun or his pogo stick, which makes him jump and avoid obstacles. Other items that he can find and be useful to him are ammo, gems and keycards.
Wikipedia: https://en.wikipedia.org/wiki/Commander_Keen