It's simple really, you just don't make any mistakes. Be perfect, but set your targets lower. With gigantic games that are full of ambition they can never hope to deliver on, something as simple as a propeller- propelled kiwi, flying through some nifty levels to some fun music is really cathartic.
It just feels good to play, the controls and motion is smooth, the area's are fun even if their not very unique, but more importantly, it ticks the boxes in my brain of being fun and rewarding. It's not really a huge challenge to master the levels, or requires practice to get it's movement; it take about 10-15 minutes at most to conquer it's simple controls, figuring out how to get to things and then flying or jumping to them isn't even hard, but it's just *rewarding*.
The only way the game could be any worse if if you had higher standards of a cheap game that just wants you to go collect stuff.
The only way the game could be any better is if it offered me a sandwich at the successful completion of every level.
Perfection