The original Sly Cooper may be my favorite platformer ever. The extended platforming sequences are a ton of fun. The departure that Sly 2 took was a disappointment, and I only started getting into it towards the end. I picked up the 3rd to finish off the series, played almost through the 2nd episode and I haven't felt the urge to keep playing it. The missions are way too short and just kind of boring. The 3D is a bad gimmick, and there isn't much of a story yet pushing me forward.
My backlog is so big that I don't feel like wasting my time. Is there something out there special waiting for me if I keep going?
This is exactly how I felt about Sly 3. I thought Sly 1 was an inventive, fun game. I'd put it in my Top 5 favorite games for this console generation in fact. Sly 2 was still a good game, but it was a definite step down from the first one. I got about two hours into Sly 3 before I permanently shelved the game. I was on the mission where you have to bounce the hippo around like a basketball when I realized that it was completely stupid and it wasn't worth slogging through pointless filler to get to a few short platforming missions.
It's a shame, because the Sly series is such a fun and visually distinctive series.