SpammerTyper

SpammerTyper has most of the standard mechanics of any typing game, with the exception that the spawn rate of letters is inversely proportional to your zoom level, which increases when you hit non-whitespace characters and decreases when you hit zoom. See the GitHub repository for more details.

Openness:

• Open source Orx game engine
• Tools: uhhh vim and g++?
• Runs on all platforms, tested on Linux
• Has a repo
• Well I could've written it on any platform, but I did use Ubuntu while writing it, if you'll take my word for it
• Assets available under CC BY-NC-SA 4.0