You're not alone. It's widely considered the best Kirby by those who've played it and does everything well. Robobot is basically a perfect game.

• Story is kept light, fun and unobtrusive but has this oddly deep and mature lore on the side. Totally unnecessary but a nice slice of content for the interested.
• Level design is traditionally Kirby's weak spot. Robobot aims for a puzzle focus which succeeds. Sharp, varied stages with solid puzzles and good pacing.
• HAL hit a home run with the riders, a perfect gimmick to complement Kirby's standard ability system.
• Considered visual design. It's easy on the eyes and there's a really nice "technology integrating with nature" motif carried out in enemies and backgrounds.
• Good combat is expected in the "KSS-likes" and Robobot's the best of the bunch. Great assortment of speed, movement, range and power abilities and combined with riders it's the deepest mechanically.
• The final moments are unironically gamer chills. So well done. If you haven't played Robobot don't spoil yourself and get on it.

A way to gauge how close to perfect something is, is asking what you'd change. What would I fix with Robobot? I think there's one too many autoscroll shooting segments and the 100% reward shouldn't require sticker grinding. That's all. It's on the cusp of an Olympic 10.

Sort of sad how this game's reputation has been sitting at "great Kirby game" which sells it short. There are lots of great Kirby games. Robobot is a first balloter for platforming hall of fame. Do try it if you haven't already.