The words "today I have a bad day " are displayed frequently along the sides of some of the tracks. Why would I want to play a game that makes me feel worse about myself?
No difficulty settings, so there's a large group of people who can't pay this. Having an option for constant rails/no gaps for the young,old, and disabled would be nice.
Most of portals have a very narrow entrance, so unless they're easy to jump into they're very difficult to get into. The decorations often get in the way of game play. Much of the track is off screen, so there's no way to prepare for what's about to happen.
There's no info on how to unlock certain marbles, like the Influencer (10,000 emojis) and Unicorn (100 successful exits), etc. You just have to stumble upon them.
The final marble is unlocked after beating the final level. So it's not needed for anything...
You start on a random track every time, so each level after about level 5 is just as potentially difficult or easy as any other level.
Achievements aren't always acknowledged. For instance I maxed out all 3 boosters, but it says I'm only 66% done.
The boosters make it more difficult to time jumps because it's harder to see the edge of the marble.
Some of the worlds are fun to explore, though.