It's been a while, but mostly it's because you're often wondering what the heck at all to do. And it has some really frustrating, outright stupid stuff, too. Like the whole sequence in the arcade. Terrible.
And then, even a bog standard, bland, paste&copied-from-Granny's-logic -puzzle-book-puzzle like figuring out how to mix a potion can take longer than you'd imagine.
Spoiler:The hints given to you seemed to be broken to me in that case. Could have been just me, but my solution made perfect sense to me, yet it never worked out. Even after consulting a walkthrough, I still haven't figured out why it worked how it did.
I don't remember much of the the second half of the game, because it seemed to get a tad meh after a colourful start
Spoiler:with Floyd getting captured, him escaping a prison, crash landing on a foreign planet inhabited by funny aliens..
It's not a bad game, though. You might take some of my harsher words with a grain of salt, since I've never understood the extreme fanboyism for Simon, either.
