Wario Land 2, level 1-1, by foundsoundfoundation.
Level 1-1: Turn off the alarm clock
A bit messy - doors lead to rooms that are directly behind the room you’re in, hence the excessive diagram arrows for directions. I think I got this game for my birthday around ‘98 or so, and played it on and off for the next 2-3 years until I unlocked everything.
The first level is no slouch. While fairly straightforward, there’s an abundance of hidden rooms and coin caches on your path - enough for you to reach your level max, with some diligence.
Now, Wario Land 2 featured a ton of secret/alternate levels - exactly half the stages, in fact. Most of them were simple enough to find - break a wall here, find a hidden platform there - except for one. It was deviously, devilishly, sadistically hidden… in the very first level. In such a way that it’s impossible to find it except by accident.
As a kid, I scoured this level. I broke into every nook, cranny and crevice. Walls were attacked from every angle. Floors were stomped. Ceilings were headbutted. Vast amounts of coinage was accrued, but no progress was made in finding the secret exit. Until… well.
You see, you start the game with Wario dozing off in bed. Hit any button and he wakes up, starting the adventure. However, if you don’t wake him… the level ends. You’re shown a cutscene in which the villains, instead of absconding with Wario’s treasure, simply kick him out of his own home while he’s asleep. Bam, new set of levels. Your reward for not playing.
And that’s how level 1-1 was burned into my brain.