It was a perfect storm, really, a combination of events against which I was powerless.
Recently having played through Athena on the NES, I was in the mood for more action-adventure goodness. World of Warcraft was down for maintenance, so my lunchtime gaming was in jeopardy. I turned to Steam and saw an ad for Sega Genesis Classics, most of which I already own in one form or another on PS2 or 360, but... hang on... what's this? Wonder Boy 3: Monster Lair?
So I bought it. It was only $2.99, after all.
It turns out that it's not the game I thought it was. I wanted another hybrid RPG action-adventure game, but Monster Lair is actually a... shooter?
Oh, and if you're wondering, it turns out that there's the main Wonder Boy series, and some of those entries are part of the 'Monster World' sub-series. The Monster World sub-series is the one with the exploration and RPG elements I craved. So Wonder Boy 3: The Dragon's trap on SMS is actually Wonder Boy 3: Monster World 2, and the Sega Genesis game I was expecting is actually Wonder Boy 5: Monster World 3, or as it was called when it was released in the U.S., Wonder Boy in Monster World.
How could I ever have confused that with Wonder Boy 3: Monster Lair?