Jump on a trampoline with your opponent and try and time your jumping to trip them as they land. Score points for time spent off-screen above, first to 250 wins. Single-button controls, more detailed info on the game's website.
The idea came from one of Mike Geig's pitches, which literally was just jumping on a trampoline trying to slip up your opponent. It relates to the heartbeat theme via the concept of timing and rhythm. Originally, I had planned on going with that simple mechanic, and making it primarily a deathmatch game with no combat, as soon as one player slips the round would be over. However, that model provided no incentive for the player to really time their jumps properly, or really jump at all. If they never tried to jump, they could never lose. Thus, I decided to add a point system in which players get a point for each frame they spend off the top of the screen. After implementing this, I decided the tripping mechanic should primarily just serve as a punishment and allowed the player to mash out of the tripped state. Originally, I had planned for multiple characters, I have designs for 5 fairly unique characters that don't stray terribly far from the core mechanics, but alas, I had not near enough time implement them all, nor could I have using only the free version of Construct 2 (which I had never heard of prior to GGJ2013, I learned it all the first night thanks to Jarryd Huntley and Josh Kruszynski). I really like the concept and I plan to expand upon it. Grab a sibling or a pally and fire it up! Hope you enjoy it!