the heartbeat is actually the stamina lol, your heart rate can increase to a point where you get tired and cant move fast for a moment as it recharges, and risk is a minor mechanic but basically you take more damage the more stars you have, and in most cases that is entirely dependent on how fast you're moving. the game could definitely use more of a tutorial to explain all these though. thank you so much for playing and giving a speedrun a shot!