Add a Homing Attack in Sonic 3 and Knuckles

(Original guide by Sonic Pro1)

by the way this is a semi-homing attack (Air Dash)

first you must have a code editor and the dissambly: sonic 3 & knuckles

I recommend context

well you should go to sonic3k.asm

then go to ; loc_119F6: Sonic_InstaShield:

and replace that for this

loc_119F6

Sonic_InstaShield:

               btst #Status_Shield,status_secondary(a0) ; does Sonic have an S2 shield (The Elementals were already filtered out at this point)?
               bne.w locret_11A14 ; if yes, branch
               btst #Status_FireShield,status_secondary(a0) ; does Sonic have a Homing Attack?
               move.b #0,(Shield+anim).w
               move.b #1,double_jump_flag(a0)
               move.w $650.d0
               btst #Status_Facing,status(a0) ; is Sonic facing left?
               beq.s loc_11958 ; if not, branch
               neg.w d0 ; reverse speed value, moving Sonic left

loc_11958:

               move.w d0,x_vel(a0) ; apply velocity...
               move.w d0,ground_vel(a0) ; ... both ground and air
               move.w #0.y_vel(a0) ; kill y-velocity
               move.w .$2000,(H_scroll_frame_offset).w
               bsr.w Reset_Player_Position_Array
               move.w '-$4A,d0; play homing-attack sound
               jmp (Play_Sound_2).l

And go higher where this is:

loc_1192C:

Sonic_FireShield:

and replace that with this:

loc_1192C

Sonic_FireShield:

               btst	#Status_Invincible,status_secondary(a0)	; first, does Sonic have invincibility?
               bne.w	locret_11A14				; if yes, branch
               btst	#Status_FireShield,status_secondary(a0)	; does Sonic have a Fire Shield?
               beq.s	Sonic_LightningShield			; if not, branch
               move.b	#1,(Shield+anim).w
               move.b	#1,double_jump_flag(a0)
               move.w	#$800,d0
               btst	#Status_Facing,status(a0)		; is Sonic facing left?
               beq.s	loc_8CB09				; if not, branch
               neg.w	d0					; reverse speed value, moving Sonic left

loc_8CB09:

               move.w	d0,x_vel(a0)		; apply velocity...
               move.w	d0,ground_vel(a0)	; ...both ground and air
               move.w	#0,y_vel(a0)		; kill y-velocity
               move.w	#$2000,(H_scroll_frame_offset).w
               bsr.w	Reset_Player_Position_Array
               move.w	#$43,d0			; play Fire Shield attack sound
               jmp	(Play_Sound_2).l

ready you already have a semi-homing attack in sonic 3 I hope you have fun and that you are happy