* {
  padding: 0px;
  margin: 0px;
}

#game {
  width: 500px;
  height: 200px;
  border: 1px solid black;
}

#character {
  width: 20px;
  height: 50px;
  background-color: red;
  position: relative;
  top: 150px;
}
.animate {
  animation: jump 0.3s linear;
}
@keyframes jump {
  0% {top: 150px;}
  30% {top: 100px;}
  70% {top: 100px;}
  100% {top: 150px;}
}

#block {
  width: 20px;
  height: 20px;
  background-color: blue;
  position: relative;
  top: 130px;
  left: 480px;
  animation: block 1s infinite linear;
}
@keyframes block {
  0% {left: 480px;}
  100% {left: -40px;}
}