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 12 -  EMF Chamber and Hydraulic Lifter

Another chapter, another two levels activated.

When I originally designed these levels, I had a rough idea of what I wanted but I hadn't fully fleshed them out. Normally I would design the level layout, gameplay, graphics and timings first and then I would code it. But with these levels, I just winged it, developing the idea as I coded. A very organic and constantly changing process but the final results have ended up with two fun and challenging levels.

New Game Loader

I decided to jazz up the game loader screen with some SG4 graphics and added a loading progress bar. It's nothing fancy, just a BASIC program that loads all the relevant files into the required locations then starts the game. The user just types RUN"ZEROHOUR".

The graphics were stored directly into the lines of BASIC code using another CoCo BASIC program I wrote in the late 80's called GRASS  (GRaphics ASSembler). It was a simple tool I created that allowed for the fast, compact and simple display of graphics in BASIC by simply PRINTing the lines or strings to the screen. 

EMF Chamber

This level was partially inspired by my recent game on the TRS-80 Model 1, Gem Hunter. In this level, you are able to fall to a greater depth (when in the green area) allowing you to transfer from one platform to another. The platforms appear in random positions at the bottom and travel upwards between the two EMF generator posts. You're character dies if he is pushed up or falls down into these posts.

EMF Charges randomly appear on these platforms which you will be able to gather to use in other levels.

Surviving the platforms is key here, made more challenging by the random positioning of the platforms which force you to plan ahead in case a platform doesn't appear where you need it.

Hydraulic Lifter

A special lifting platform designed to lift heavy freight up to the platforms above.

It is powered by EMF energy which you must load into the lifter by inserting some of your collected EMF charges to power the lifter to the desired height you wish it to move to. The lifter will then reset itself by lowering automatically and you must use the slides (the blue tubes) to safely return to the bottom platform.

This a level where you must have collected enough EMF charges to operate the lifter since you will be required to ride the lifter multiple times to deactivate the robots and reset all the security switches in that level.


I also had to fix a few bugs that I let creep in to the game. One was where your character could jump off the right side of the screen and reappear on the left landing on the platform there. That was fixed.

I've tried to speed up the main level lifts in the Foyer by allowing you to reverse the direction of the lift and avoid waiting so long to complete its automated up/down cycle.

I also needed to add an extra death sequence for when you die instantly rather than just falling, such as touching the EMF generator posts. You now get a zapping effect and disappear. You are then respawned at the door entry of that level with your next available life.

And lastly, the piece de resistance feature of the entire game, there is now the famous line by the CoCo community's shining superstar David Ladd that says "REALLY?" when your character has met his doom.   :)


Click on the image below to see a YouTube video of these two levels as well as the two levels from my last blog chapter.

There is still a lot more to do. The robots still can't harm you, the EMF bombs (yellow squares) are now displayed but I can't collect them and the status readouts at the bottom of the screen still don't function. These will be a job for another blog chapter.

Copyright 2021 by Nickolas Marentes