I've had my eye on Gunman Clive, a downloadable title for 3DS, for a while. It got great reviews and it was only $2, and people praised its Mega Man like mechanics. Although I enjoy the Mega Man series, I'm not an uber-fan, so it took Clive's inclusion in the Nindies Humble Bundle to get me to finally download it and give it a try.
The game is amazingly well polished, and enjoyable from its start to its ~45 minute later end (on normal mode with the main character). As expected, the Mega Man influence is very strong, but the game has its own personality and offers a number of surprises as well, in the form of boss fights, weaponry, and stage hazards. The game packs a ton of variety in its short length, and there are two additional characters to play as (the unlockable one was such an awesome surprise I found myself grinning in a way usually reserved for first-party Nintendo titles), an additional hard mode, and target times for every stage.
I was suitably impressed with the game and, in true Humble Bundle success story fashion, immediately bought the sequel. I started it and it looks like more of the same although with a higher difficulty, but I'm still looking forward to finishing it before too long to see what surprises may be on store.