Runner 2 is broken because of its non-stop pace, lack of checkpoints, and clumsy controls.
Runner 2 was a fun game for me, but relatively so. There are five areas. It was fun at the beginning, but after the first two areas I just wanted to finish it. In the first two areas I played all the levels. In the fourth and fifth areas I just played straight through. When I finished I was relieved and felt no desire to replay any of the levels to collect costumes, get trophies, or compete on the leaderboards.
In Runner 2 other than jumping there are a few other actions you can do. You can kick obstacles that block your way. You can slide, slide-jump, and slide-kick. You can use a shield to deflect objects. Cross is the jump button. Slide is the down directional arrow. Block is the right directional arrow. Kick is the square button. Since the game is always moving at the same speed, the controls can be clumsy. Near the end of the game especially there were times where I needed to glide kick, but in order to do so I needed to hold down the cross button and simultaneously press the square button at the right time. Problem is if I let go of the cross button I would fall and restart at the last checkpoint.
I only played the game on the normal difficulty. On other games I like to play on the hardest difficulty. Since Runner 2 is low on the checkpoints, high on the difficulty, and clumsy on the controls I probably won't play it on the hard difficulty. I imagine that with the increased difficulty the controls would become clumsier.