Ninja Spike Avoider is a simple 10 level platform game of jumping and
avoiding spikes while trying to collect all the coins on each level.
It is an open source game made with Tad's Basic Game Objects (tabageos)
an open source library for quickly making html5 games.
And there is a complete tutorial series that goes over how to code the game from complete scratch,
by extending the tabageos GameSkeleton class it takes less than 400 lines of code to make the game,
including a title screen, level select, sounds, touch support and game pad support.