Last Battle: Legend of the Final Hero is a side-scrolling action game similarly to its predecessor Black Belt. The player takes control of Aarzak (Kenshiro in the Japanese original), who fights against his enemies using his punches and kicks. Aarzak can attack while standing, jumping, and crouching, for a total of six basic attacks. In addition to his life gauge, Aarzak has a power-up meter that will gradually fill as he defeats enemies. When the meter reaches a certain point (depending on the stage), Aarzak will transform into a super-powered state, allowing him to perform rapid punches and kicks for the rest of the stage. The game's levels (with the exception of boss battles and maze stages) feature a time limit at the lower-right corner of the screen; but unlike other time limits, instead of killing the character immediately when it reaches, it will instead gradually drain the player's life gauge until the player completes the level.

The game is divided into four stages or chapters, each featuring several levels. After completing a level the player will be shown a map which displays the player's current location and the paths they can take. Most of the levels are linear side-scrolling segments where the player must simply walk from one to side to the other while fighting every enemy who gets in the way. Other levels are dungeon mazes in which the player must figure out the correct path to the goal while avoiding traps. The player will encounter various allies throughout the game that will increase Aarzak's offensive or defensive strength, or replenish their health. The game features several one-on-one encounters with bosses as well. The player must sometime complete levels in a certain order in order to finish a chapter.

'Last Battle' is also notorious amongst gamers for its harsh difficulty throughout.

The original Japanese version is based on the Fist of the North Star mangas/animes. During the translation process all references to Fist of the North Star were removed - similar to its predecessor Black Belt.