The 1st Wario Land might be the Mario game that has been worst affected by age. You can see it kind o’ attempt very forward-thinking elements for 1993, including its focus on collecting coins with actual rewards for doing so beyond a high score & extra lives & the focus on finding hidden treasure in levels, making this arguably the 1st collectathon platformer, &, as part o’ that, its alternate endings.
But I say “kind o’ attempt”, ’cause Wario Land doesn’t do much with this collectathon aspect beyond different endings, & I would say it didn’t implement them well. Treasures basically just act as alternate exits like in Super Mario World, including requiring carrying a key to a keyhole, which is on top o’ this game having alternate exits, too, including a whole bonus world that doesn’t offer any tangible reward for completion — contrast to Super Mario World’s fun reward for beating Special World. & as we’ll see, Wario Land’s treasure & alternate exit puzzles are not nearly as clever as Super Mario World’s.