Parallax is "the effect by which the position of an object seems to change when it is looked at from different positions" (Cambridge Dictionary).
In side-scrolling video games, we get this effect by overlaying background images that move at different rates. The more distance the object, the slower it moves. On the gamedev server, there is an example program that shows a background mountain range, with trees in front of it. As the player's character moves right (or left), the trees move quickly and the mountains move slowly. Actually, the player's character does not really move; the scenery moves. The exception is when the character jumps.
The example game does not present a challenge. If the player moves the character far enough to the right, it will reach a flag and win.
Copy the example to your public_html directory, then add some obstacles and platforms. You could use the brick wall tile for a platform. You will need to adjust the movement actions to make the character jump and move at the same time. Currently, it jumps straight up, though you can get it to move a little to the right or left once the jump starts. It would be better if jumping and going right causes the character to continue to move in an arc. If the player lands on top of an obstacle or platform, the character should be able to walk along the top of it until they jump or fall off.
Have at least one trap: an obstacle that the player must avoid. Use a tile other than the wall tile for the trap. You are encouraged to make your own trap tile.
If the character falls, we can assume that it does not get hurt. If it makes contact with a trap, you can halt the game and turn the screen's background red.
Feel free to make improvements. For example, the animation is not as smooth as it could be. Or you could use a different character sprite sheet.
Turn this in through iCollege: a link to the html file, a copy of your html file, copies of any javascript files that you created, and the data files.