in the game's second
level Sonic Blast is a 2D
side-scrolling platform game. Its story begins when
Doctor Robotnik shatters a
Chaos Emerald into five shards with a laser. One of the shards hits
Sonic the Hedgehog, who, with the help of
Knuckles the Echidna, sets out to prevent Robotnik from collecting the other shards and fortifying his island base. Sonic and Knuckles serve as the
player-characters of the
single-player game. Sonic, in addition to his spinning attacks from prior
Sonic games, has a special double-jump that gives him a secondary jump in midair. Knuckles retains his abilities from
Sonic & Knuckles: like Sonic, he can perform spin attacks, but can also glide through the air and climb up walls when he hits them in midair. The player travels through 15
levels (called "acts"), across five parts called zones. Every third act contains a
boss fight against Robotnik and one of his larger robots. Zones range from the traditional
Green Hill Zone to underwater ruins, and feature
vertical loops, slides, and teleporters. In the
Sonic series tradition, Sonic and Knuckles collect
rings as a form of
health. Rings serve as protection for the animals, defending them from the attacks of
robot enemies. When taking damage, ten rings scatter across the stage and can be recollected before they disappear. The player starts the game with several
lives, which are lost if the player is crushed, drowns, falls into a bottomless pit, or is hit with no rings in their possession. Losing all lives results in a
game over, after which the player is returned to the
title screen and must restart the game.
Power-ups hidden in television monitors provide Sonic and Knuckles numerous boons, including more rings, a burst of speed, shields,
invincibility,
extra lives, and the ability to save progress in a level. Some monitors, however, contain Robotnik's face and do not grant the player anything. Others contain question marks, which grant any of the power-ups. At the end of an act, the player must hit a signpost to complete the level. The signpost will spin until it lands on an image; the image will grant the player a reward. Similar in fashion to
Sonic the Hedgehog 3, giant rings leading to special stages are hidden around levels. The special stages follow the same basic format of those in
Sonic the Hedgehog 2: the player-character runs forward and must collect rings to meet a required amount. They must avoid bombs, and sometimes will jump, run on boost panels, or hop on springs to get more rings. Successful completion of special stages will grant the characters extra lives, rings, or one of the Chaos Emerald shards. ==Development and release==