KNIFEMAN VCS Game

• 06 September 2022
• notes,
• VCS,
• Atari,
• gamedev,
• lazy

# CONCEPT PITCH, NOT A REAL GAME (YET)

DAVID KNIFEMAN has escaped from Knife prison! Descending on the idyllic suburbs of stabbyville, he stalks his next victim...

"Halloween" style slasher game for the Atari VCS (2600). Victim is stalked by KNIFEMAN, escaped maniac. Collect items (why?) within time limit to escape, but don't get caught!

# Play concept

Knifeman has to catch the victim 3 times to win. On capture, Knifeman is frozen, screen flashes and victim has a few seconds to start running. Big-ish world map (6x6 rooms?), adventure style 4-way traversal. A house, maybe a school, a few streets, etc. 3 items to collect, scattered around map in random rooms

# 1 player

# Play as victim (Mode 1)

• Escape, collect items for points, collect all to win, final score is time adjusted.
• Needs chase AI for Knifeman

# Play as knifeman (Mode 2)

• Kill victim before they collect items.
• Needs running away AI for victim

# 2 player

# Player 1 is Victim, 2 is Knifeman (Mode 3)

• Horizontal Split screen, each can be in separate rooms
• Same win/lose conditions as normal

# Sprites needed

• KNIFEMAN, 2x walk frames, 1 stab, 1 death
• VICTIM, 2x walk, 1 pick up, 1 death

# game juice

• Asteroids style heartbeat BGM, gets faster as knifeman approaches?
• Occasional thunder & lightning changes the stage BG colour, sound cue.
• Use sprites to decorate areas player cannot reach (doors, windows, furniture?)
• Screen transitions to win/lose screens (Vertical scroll in new page )

# Tech stuff

# Variables

Static

GameMode VictimX, VictimY, VictimRoom, VictimHealth, VictimCompletion KillerX, KillerY, KillerRoom, General Purpose

X, Y, I

# Sprite handling

Use doublesize sprite for knifeman Items use the "Bullet" object

# AI

AI goes into simple mode when not in same room as player, waits X seconds and then changes to different room, no active collision logic. On entering room with AI in, position them in random spot far away from entry door so you don't get immediately jumped

# Knifeman AI

• Chase VICTIM,

# Victim AI

• Go to centre of room
• If item is in room, beeline for that
• Pick a door other than one entered by (unless if it's the only one available) and head for that

# Screen kernel idea

# every line

• Load terrain and push to PLAYFIELD registers
• inc VICTIMSPRITEY and KILLERSPRITEY variables

# If split screen

• Figure out scroll points for each viewport
• Start video kernel on first point
• Once 94 ( (192 / 2) - 2 ) lines drawn, blank screen for a few (4) lines
• switch room register, load in new scroll, load resume drawing

# If in transition

• x = 192 - Transition
• Process X lines as as necessary
• On line X, jump to transition screen draw logic
• End on line 192 as normal
• Decrement transition var until 0

# If split screen & transition at same time (Widen the split in the middle of the screen to show message)

• x = ((192 / 2) - 2) - Transition
• Draw X lines as normal
• On line X, jump to end screen logic
• x = x + (Transition * 2)
• on line X of end screen, return to game render loop