Rainbow Runner is a map solely based on redstone and command blocks, so make sure that you have command blocks enabled or the map wont function!
Upon entry into the map you will start in a room made of iron blocks and lined with pink and light green wool, if this is not so then please say so in the comments and I will try to resolve the problem. Anyways.. There is a chest with golden apples on the floor in the case that you get hungry, we wouldn't want you to die...hehe..muahaha...muahahahahahahaha... There are two buttons on the wall, one allows you to play the easy version of Rainbow Runner, and the other button, the hard button, allows you to play the hard version of Rainbow Runner.
Your main objective as stated above is to avoid the parts of the rainbow that come hurtling towards you. Remember, when you get hit by the rainbow your turn is up. The map will then automatically reset and teleport you back to the starting room. During the game you will earn levels, or xp, this is a counter for how long your game has been lasting for. You get a level every 1.576 seconds (yes I did infact do the math for that.) When the game ends you will stop earning levels, upon the start of a new game, the levels will be reset to zero (0).