It's a cute little visual novel with the Sonic characters, not a lot more can be said. The visuals are phenomenal, the gameplay is... Well... It's a visual novel.

I think over all the game overstays it's welcome a little bit, but there isn't much to complain about since it's free. Definitely the best April Fools joke I've ever experienced.

(Spoilers for the game mechanics)
There's this minigame you have to play to "think". It's fine but it gets super annoying towards the end of the game. You have to constantly play the game back to back and it gets old fast.