Played the game a bit. Watched a video, then did a full game clear, in 1 hour of ingame gameplay.
Then spent the rest of the time doing the challenges for RetroAchievements in level order, like timeouting bosses nmnb and beating stages separately nmnb. I spent a similar-ish time on everything, with the final level being a bit more difficult (and with less restrictions!)

Good scoring attempt.

Failed scoring attempts.