I enjoyed my time with this puzzle platformer. The mechanics make sense.
I found a small sense of delight when I discovered that the duo could attach with blue fella on top, not just blue fella on bottom, giving me options and expanding possibilities.
One thing I found unintuitive: when the shell switches are introduced, they have to be stood on constantly or else they turn off. Later in the game, a shell that looks exactly the same no longer follows that rule.
If a live reaction would be useful for you, you can watch a video of me playing it here. https://www.twitch.tv/videos/1058833315