I have made my first project with Gosu and Ruby, Gem Collector with Gosu. It's just another platform game, but I'm quite proud of it, considering that I have programmed it during my time every day on the train. Feel free to give your opinion and suggestions, considering that I dedicated just a few hours to make the game. You can get more info, in Spanish, in my personal blog, Juan de Frías, http://www.juandefrias.com
All the code is in my github, http://github.com/juafrlo/Gem-Collector-with-Gosu
I have a video here also: http://www.youtube.com/watch?v=_VmOiZVc7pM

Thanks!

looks nice, a good base for a mario style game :) Are you planning on taking it further? :)

It's possible that I will put some new things. In fact, I hace changed one a few days ago. When killing an enemy, the player goes up a litte and then goes down to the floor, not going straight to the floor when killing the enemy.

Nice. I think you should look into Chingu or benko's shooter game here on the Showcase to split the game up into proper game states (always a good thing when going beyond the examples)! :)

Your game looks interesting,Keep up the great work mate!