Whenever thievery is the focus of a game, it's natural to assume that the result will fall into the stealth genre. Tiny Thief, developed by Barcelona indie studio 5 Ants and published under the Rovio Stars umbrella, does have a little bit of stealth, but it's more point-and-click adventure than full-time sneak-'em-up.
We can be even more precise than that, in fact. Tiny Thief belongs to a very specific subset of the adventure genre, best illustrated by Amanita Design's Samorost browser games. Let's call them click-and-see adventures. Rather than basing progress around the accumulation and unlikely combination of inventory items, these games simply present the player with charming little interactive dioramas where prodding stuff to see what happens is the basis for success.
That doesn't mean that there's no skill or thought involved. As Tiny Thief's tiny thief, you have six quests to work through, each made up of several distinct scenes. In each one, there's a specific object you have to pilfer in order to open the exit. The item in question is generally connected to some overbearing authority figure or similar bully - Tiny Thief is more Robin Hood than hoodie thug.