Here's an old classic. When I was little, I remember watching my dad play Commander Keen in Goodbye Galaxy! Episode 4: The Secret of the Oracle. This is the fourth episode out of six total about boy genius Billy Blaze, who is better known under his hero alias "Commander Keen." He is part of the Blazkowicz family which includes other ID Software legends such as Keen's grandfather B.J. Blazkowicz from Wolfenstein and his son Sergeant Stan Blazkwoicz, better known as Doom Guy.
Blaze has travelled throughout the Galaxy in his Bean-with-Bacon Megarocket encountering many fantastic creatures, including his pet Yorp, Spot, shown here. He has gained the respect of many races including the Vorticons and the Gnosticenes.
There were originally supposed to be nine episodes, but the ID Software group got too hung up on other projects and ended up abandoning it.