*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    display: flex;
    align-items: center;
    justify-content: center;
    background: greenyellow;
    min-height: 100vh;
}
.container{
    width: 300px;
    height: 600px;
    border: 1px solid green;
    background: #fff;
    position: relative;
    overflow: hidden;
}
.character{
    width: 100px;
    height: 100px;
    background: green;
    position: relative;
    top: 500px;
    left: 100px;
}
.block{
    width: 100px;
    height: 100px;
    background: red;
    position: absolute;
    animation: train 0.7s infinite linear;
}
.left{
    position: absolute;
    width: 50%;
    height: 100%;
    left: 50%;
}
.right{
    position: absolute;
    width: 50%;
    height: 100%;
    right: 50%;
}
button{
    position: absolute;
    bottom: 0;
    width: 80px;
    border: none;
    padding: 7px 0;
    background: #CCC;
    border-radius: 5px;
    color: green;
    outline: none;
}
@keyframes train{
    0%{top: -50%;}
    100%{top: 650px;}
}