I played it closer to when it came out and hat fun with it. The humor was pretty good, I still remember some of the jokes. If I recall the main game wasn't too hard, but it had some tough bonus levels, or finding everything for 100% was a bit hard? Not too sure anymore, but I think I managed. It's not super meatboy level difficult.
i only played a bit when it came out like half a decade ago, but gameplay wise it felt kinda like Super Mario Sunshine/64 with the aesthetic of Wind Waker + Super Mario Galaxy