Really enjoyed what I could play of the game but I found that it was just a bit too difficult for me

I really liked the take on the theme! The graphics are pretty interesting as well, being made in just 2 days. I thought jumping in the air was a bit odd, but then I noticed that the stamina gets lower every time. Some music in addition to the heartbeat would be nice in my opinion: you could make it get heavier (or slower/faster) when the player had a heartrate that was too low or too high :)

Nice game! It's simple, and looks very polished, which is well done for only 2 days of work. The only thing is that the fact you're specifically looking after your "heartrate", which doesn't really mean something in the game. It could just as well be "points" or something. But that's a minor complaint, overall, really well done!