Wait, is there another way to play than 100% and ALL achievements ?

)
There is some hidden truth in your sarcasm.
For years now, editors have tried to inflate the players game time. This is done through grindy mechanics, achievements, DLCs, to keep you engaged in the game.
We, as players, have become used to it, and -dare I say- desensitized.
But Holiday Island if not that type of game. By its very nature, it cannot be.
It's a porn game. There is no boss nor achievement that can motivate me to play longer: when my balls are empty, my balls are empty.
There is one major criticism that can be made against HI: The UI is full of information, quests, stats, boxes to checks, etc.
It looks like a grindy game, whereas the core gameplay loop is anything but.
This mismatch between the UI and the gameplay is possibly the game's biggest design mistake.