Short version:

Clicked on the top leaderboard name that had an island, and when it loaded the game, it gave me two achievements: Tropico for the Tropicans and Down with the Tyrant. Any way to trick the game into removing those achievements so I can actually earn them properly?

Long version:

So... I had just finished the first level when I noticed you can upload your island, so I clicked it just for the hell of it. Then I found my name on the leaderboard, and sure enough, my meager island was there to download (so now you can see yourself what a 54,000th place leaderboard island is like). Curious about what the higher scoring islands might look like, I clicked on the one in 12th place by F. Davie, and got two achievements as soon as the map loaded: Tropico for the Tropicans and Down with the Tyrant.

I'm one of those people that enjoys earning things for themselves, so even though I know I can't remove the steam achievements from my history, I wonder if there's a way to trick the game into marking those achievements as locked again. If anyone knows, please reply. Thanks!

Found an easy solution. Created a new profile, which had no achievements unlocked. Earned them properly this time!