Great game. I like the difficulty progression with the icicles going faster. You could add some white pixels to make the icicles look less like stalagmites. Also, adding in different sprites for left, right movement and jumping and falling would work well. I tried jumping on top of an icicle thinking I could land fine but got hurt instead. So maybe adding 1 or 2 pixels on top could indicate it's still a hurt area. Lastly, you could add a death animation but then you'd have to decide how kid friendly you want it to be. I like that the coins disappear after a certain time period. Gives a little bit incentive to try to get your score up as quickly as possible. Nice job!