I came in wanting to like Shadowgrounds. I thought "hey, I can handle this, I cut my teeth on games way tougher", and it just didn't turn out that way. Call me spoiled, but since the days of Half-Life with its convenient autosave points, I have no desire to punish myself repeatedly trying to beat a game. Heck, I was tired of that way back during some of the tougher missions in X-Wing. Give me an action game, give me a puzzle, but don't give me both at the same time while limiting my respawns and forcing me to start over every level.
On the other hand, if you do crave that kind of challenge, I cannot think of a game better suited to deliver than Shadowgrounds. I'd scarcely be surprised if the development office was right next door to a dominatrix's brothel.