For anyone interested, I’ve made a short, silly 2D game in SDL2, where the objective is to rescue a bunch of stranded aliens. There are 5 stages in total. It also supports an in-game achievement system, known as Medals. There is online functionality, too, so you can generate a medal key and use it against a server.
Windows and Linux binaries are available. Again, short, and will only take you about 10-15 minutes to finish (maybe 30, if you go for all the Medals).