Super Boy Description: Super Boy I is a Korean-made unlicensed conversion of Super Mario Bros.. It imports the sprites of Mario and all of the enemies, terrain ingredients, as well as basic gameplay mechanics. The levels resemble those of the original game, most notably the earlier ones; however, only outdoor areas and simplified castles (some without any enemies except Bowser) are included. The game ends after three worlds, each divided into three stages and a castle level.

This version omits much of the material found in Super Mario Bros.. There are no power-ups except the mushroom (which is placed randomly); no warp points; no bonus levels; no cave or underwater areas. Falling platforms replace elevators; pipes cannot be entered. Castles can be completed without defeating the guarding Bowsers. In the castle's final area the player is greeted by the words "Sorry Nothing". The princess is not mentioned at all.