Reminds me a bit of the type of games Ketchapp release, and they are very successful 
Thanks for the compliments.
Do the different shape characters alter the gameplay much? I couldnt really work out whether they made it harder or if it was for visual effect only.
Initially the game play was that the the roller keeps rolling. The speed won't increase. By that time, the actor shapes did make a difference. The smaller the sizes were, the easier to escape. Later, I added a feature - The more you tap, the faster it rolls. Now when the actors size becomes smaller, player will have to tap more, resulting in faster roll.
With the new feature, you both have advantage and disadvantage based on the size. You'll have to check which shapes suits you best.