Finally decided
The theme didn’t seem to make my produce a lot of ideas. After some thinking, I finally decided on the game: it will be an adventure game, where your goal is to kill some evil creature (cyclops?). You are a professional knight, equipped with tons of brand new stuff. But, for more fame and glory, you decide to throw out one thing each level. By the boss you should only have ability to move right left (‘move right left’? lol? That’s actually ‘You have left an ability to move right’).
I’m also streaming the process at http://www.twitch.tv/rodzos.