In Diamond Girl player is a girl collecting diamonds. Player needs to collect certain amount of diamonds for exit to next level open.
Diamond Girl is licensed under GPL (see the LICENSE file), it was created by Joni Yrjana, contacting email address can be found from the CREDITS file.
Diamond Girl was written for Linux, though it might work on other platforms as well. It was reported to work on AmigaOS4 and MorphOS.