Personally, I don't think it was that bad.
1 hit death wasn't that uncommon in those days, and there were certainly far worse games.
The cat dying to almost everything was kind of its gimmick though. (along with giving nine lives.)
I didn't think it was that unfair (though I probably played like three worlds in at most, over half the game).
You really have to use the Glide button to get more reaction time (and also remove fall damage) to stuff, I think.
Though I'm aware it's not exactly a perfect game either. I have seen video of one badly placed checkpoint where if you don't defeat the enemy next to it first, Bubsy can spawn in an infinite death loop.