Head On

Head On
Developer: Gremlin Publishers: Gremlin, Sega Platform: Arcade (Sega VIC Dual) Released internationally: April 1979 This game has uncompiled source code.

Head On is the first dot-collecting maze game, coming out over a year before Pac-Man. Of course, as you can see from the title screen, it's not much of a maze, and you run over the dots instead of eating them.

Filler Text

There's filler text at the end of the game ROM. The text differs depending on the game version:

Head On (2 Player) (MAME: headon)	Head On (1 Player) (MAME: headon1)	Alpha Fighter / Head On (MAME: alphaho)
;MODS FOR 2 PLAYER ;8/31/79 ;9/5/79 ;9/6/79	;ERASE BONUS FBONUS: LD HL,PLAYER BIT 0,(HL) LD HL,153.341 JR Z,EBON1 LD HL,157.341 JR EBON1 EBONUS: LD HL,PLAYER BIT 0,(HL) LD HL,253.341 JR Z,EBON1 LD HL,257.341 EBON1: LD A,PBLANK LD BC,6.2 JP BOARD ;** ;PUT "BONUS" QBONUS: LD HL,PLAYER BIT 0,(HL) LD DE,13.13 JR Z,QBON1 LD DE,17.13 QBON1: PUSH DE LD BC,6 LD HL,BN1MES CALL PUTMES LD BC,6 POP DE INC D JP PUTMES PBONUS: LD HL,PLAYER BIT 0,(HL) LD DE,13.15 JR Z,PBON1	;** INIT: SUB A LD (LANCNT),A LD (DILANE),A LD (DICNTR),A LD (DIFLAG),A ;AR SIDEWAYS EV6: LD IX,CCTAB LD A,3 LD (TCAR),A LD A,(ADVERT) AND A JR NZ,EV6G ;CHANGE BITS TO DIR EXX LD E,(IX+JOY) LD B,4 LD C,0 EV6F: RR E CALL C,TSTDIR JR C,EV6E INC C DJNZ EV6F EV6E: LD (IX+JOY),C EXX EV6G: LD HL,SFT2 LD A,S1 ;** ALL CARS SIDEWAYS EV6C: EX AF,AF' LD A,EV5CLK LD (BC),A LD A,(IX+PAS) CP 2 RET C CALL SERV ;GET DIR LD A,(IX+JOY) CP 4 JR NC,EV6D LD C,A CP (IX+DIR) RET Z INC A INC A AND 3 CP (IX+DIR) RET Z ;SCREECH SOUND EX AF,AF' CALL SNDON ;MOVE SIDEWAYS ;C=DIR LD A,C CALL NEWDIR CA STACLE LD (IX+COL),0 CP HWALL JR Z,EV6A CP VWALL JR Z,EV6A CP PBLANK JR Z,EV6B ;OWN CAR? CP 15 JR NC,EV6H LD A,(TCAR) CP 3 JR NZ,EV6B EV6H: LD (IX+COL),1 EV6B: CALL UMOVE ;RESTORE FORWARD DIR EV6A: LD