Here is the full list of all 16 Oppaidius Tropical Cruise achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
You saw the Angela without panties secret scene!
You unlocked every art in the game! Now check the gallery, a surprise could await you there…
You saw all the tic tac toe boxes’ scenes!
You achieved Angela’s max level affection points!
You saw the VERY SCARY devs’ ghosts!
5 minutes in a row looking at the cleavage rubbing scene… will it be enough…? (Of course it is not)
You achieved Rika’s max level affection points!
You surely are somebody’s type-you just need to hang in there!
Look at those melons!
You heroically resisted until the end…
It’s the first time I’ve seen her smile…
Right, that’s the kind of “achievement” I didn’t need…
You set the “boobage level” to 100!
You remembered about that time, with the seagull…
You chose the wrong “shortcut”…
You began the adventure!