by Michael C Palmer

Thank you for joining our crew at Safety First Mining Company. As a runner, your job is to push your cart across the mines and pick up every gem that you can find. Push it over to the next mine once you finish. There are several objects that you might find around the mines. Feel free to pick them all up, but remember, all gems must be surrendered to the processing team at the end of your shift.

Download the APK

Browse the FTP


Gemsters is a new entry into an old genre that began with PAC-Man and continued throughout the early eighties, with many excellent entries available in the arcade and for homes consoles such as the Atari and Collision. The genre died shortly after the birth of Nintendo, but it has been reborn as an RFO Basic! project developed by yours truly.

Like many similar games, players must navigate a maze of corridors and collect a number of valuable objects scattered across them. Unlike the others, stepping on gems in this game is not enough to collect them because of their excessive weight. You must push your mine cart around the corridors and collect them in that. The mine cart works as a protective shield but could trap you depending on the direction of the monsters, and it requires players to circle and back track throughout the maze in order to get it around corners. This game mechanic sets Gemsters apart from other PAC-Man clones.


Fully animated character and monster graphics

5 touch screen controls settings and support for a keyboard or gamepad (not sure which one(s) are best)

Manual and auto mode for cart pushing (which is better?)

A decision engine that weighs at least 12 variables and conditions to determine monster behavior

7 different monsters, each with their own behavioral patterns

7 different stone textures for the background

7 sound effects for running, pushing, collecting, and being eaten

4 powerups that appear randomly during gameplay

13 levels and an integrated level editor

Level data, control options, and hi scores contained in an SQL database

Attractive menus and in-game instructions to help first time players

Menu options to rest scores, configuration, and level data to their defaults settings (copies sql db from apk)

History and Development

Gemsters was originally developed using yBasic for PalmOS devices. When considering what sort of games I could produce under platform's limitations, PAC-Man quickly came to mind. Of course I had no desire to make yet another copy of a game that had already been ported to every imaginable platform, deciding instead to make something new that might revitalize the genre.

The original game included 4 monsters graphics that were carefully drawn as 8x8 black and white sprites with very simple animations. The miner you controlled was a stick figure of the same size. Performance issues prevented me from fixing all the tiny control and logic bugs but I felt that it was an overall success.

The Android version has much improved graphics produced in the Ivy Draw App available on the Android Play Store. It was ported to RFO Basic!, a very nice open source basic interpreter. Other than that and a nice user interface, the game remains more or less unchanged.

The development was performed on an RCA Viking Pro 10.1" 2-in-1 Android laptop using the following apps.

RFO Basic! - Source code edited and tested in this free basic interpreter for Android

Basic! Compiler - APK compiled by this 3$ app

Ivy Draw - All graphics were designed in this great vector graphics app that costs 6$ to register

Pixly - minor graphical touch-ups performed in this free pixel editor

WavePad - most sounds effects were produced or processed with this 10$ app

SFXR - a few retro style sound effects were generated by this opensource app available for most platforms

OmniNotes - this opensource note taking app was used to document agendas and to track bugs

DroidEdit - associated text files edited in this free app

Known Bugs

Rarely, when a monster warps to an edge of the screen where you're pushing the cart, the monster will walk through the cart because it has nowhere else to go.

Very rarely, when you grab the cart, you will face and push it backwards. I cannot recreate this problem when I try, or figure out what might be causing it. Probably fixed.

Sometimes your character and the cart he is pushing get a few pixels out of alignment. Probably fixed.


Gemsters is public domain and may be freely used, distributed, and modified with the following exceptions. One, I reserve the exclusive right to distribute it where software is bought or sold. Two, derivative work may not use the name of Gemsters.

Questions and comments welcome in my mailbox,

Best regards