4GRAVITY!

4GRAVITY! is a  game written in ugBASIC and that runs on various 8-bit home computers like ATARI 400/800/XL/XEGS, Commodore 128 (8502), Commodore 128 (Z80), Commodore 64, Commodore 64 with REU, TRS-80 Color Computer 1/2, TRS-80 Color Computer 3, Amstrad CPC 664, Dragon 32/64, MSX, Olivetti Prodest PC128 and Commodore VIC-20.

This game is a "Connect Four" clone. It is a two-players, one-player and zero-player connection board game, in which the players take turns dropping colored tokens into a seven-column, six-row vertically suspended grid. The pieces fall straight down, occupying the lowest available space within the column. The objective of the game is to be the first to form a horizontal, vertical, or diagonal line of four of one's own tokens.

The source code is available on this repository.

This game was ranked third in the  "Forza 4" Challenge of the RetroProgramming Italia - RP Italia group. 

HOW MUCH HAS ugBASIC HELPED?

This cross-platform game would not have been possible without using ugBASIC: it is an isomorphic language and it has cross compilers that works on Linux and Windows, that directly converts high level algorithms into the assembly equivalent for the given CPU / computer.

Developing for multiple platforms requires very little effort because the source does not have to be adapted. With a single source code you can obtain programs for multiple retro computers, even very different from each other. Moreover, each target can have a dedicated optimizer, which allows to achieve very interesting results while leaving the BASIC code fully readable.