A Game Development Blog by Nickolas Marentes for the Tandy Color Computer 3.

      This blog will primarily focus on the creative and technical design aspects I employ to create this game.
      Due to time constraints, I will not be delving into the actual coding details.


Chapter 01 - Game Concept

What better way to start a new year by starting a new game development!

This time around, I have decided to go back to one of my favourite game genres... the humble platformer.

I have long been tossing around the thought of creating a CoCo3 specific version of my old time game Donut Dilemma giving it the high res 16 color treatment available on the CoCo3. But I have recreated that game so many times over the years that it's time I lay it to rest.

Another idea I had was to recreate my first CoCo3 game Rupert Rythym. This is a game which I have long felt could do with many improvements from my original 1988 release when I was still just learning about the CoCo3.

With so many ideas to consider, I have finally settled on a new game that would take elements from both of these early games and  create a new idea that is a mash-up of the two.

At this stage, I'm still working out the game details and should have a clearer idea in a later chapter but the general concept right now is that it will be a multi-level game similar to Rupert Rythym but with a goal to eventually disarm a bomb on the top floor of a large automated manufacturing firm.

Gunstar Graphics Engine Update

First thing I wanted to implement was an updated version of the Gunstar graphics engine to run in a higher resolution. But because this engine relies heavily on the moving of large blocks of memory, the increased resolution proves a very high overhead. This overhead is balanced out partially with the simplification, ease and speed improvements that this engine provides in sprite management and overlay capabilities.

To reduce the memory overhead, Zero Hour will not feature scrolling of the screen or a larger virtual play area. I have however come up with an idea for utilizing the engine in a slightly different way that will provide a spectacular new special effect which I will describe in a later chapter.

I have tested these changes and am satisfied that it will provide enough performance to provide the features I require. The final graphic resolution will be a 256 x 225 x 16 color display and feature the flexible sprite management and overlay abilities of the Gunstar engine.

Game Tiles and Level Design

Once I had the game resolution and screen dimensions worked out, I then created a Level Editor in BASIC to start designing the levels and visualize how the final game will look like.

I settled on a game tile size of 8 x 8 bytes (16 pixels x 8 lines) and used the program Brilliance 2 on my Amiga to create the Game Tiles. I then transfer these to the CoCo3 which my Level Editor reads and allows me to paint my levels using the tileset as my palette. At the same time, it is generating  a tilemap which the game code will use to recreate the level when needed.

A final feature of the Level Editor is the  visualize function which recreates the level in the position that the final game will produce along with the score and status panel at the bottom of the screen. These visualizations let me check what the gameplay logic will be and is a time consuming but very important part of the pre-planning  before any code gets written.

Copyright 2021 by Nickolas Marentes