I don't like the fact that you refer to people who solve your puzzle as "bright" and reward them while all of the people who get frustrated and can't figure it out are going to be even more frustrated when you're basically saying they are not "bright" and they are not getting rewarded.

It's basically insulting the majority of your players and I really don't see why you'd want to add something like this to your game. Achievements are great but they should be something that anyone can accomplish given enough time and effort... and also not be frustrating as all hell to do.

While your puzzle might require time and effort, it gets frustrating fairly quickly and I'm not sure that's something you really want for your players.

Sure, now that I know the answer to the puzzle it seems clever and fun. But it was not clever and fun when I didn't know the answer. There is a big perspective gap that I hope you're seeing. As the puzzle maker you're of course going to feel that your puzzle is fun and clever. This is because you know how it works. It's like the cat that ate the canary.

Since it seems that only the minority of your playerbase is going to solve these, you're going to be pissing off the majority of players.

I think the fact that several people have even went as far as to say they wouldn't pay for your game or they would uninstall it or stop playing it based on this one puzzle should give you some indication not to include this sort of thing in your game.

Unless of course, you hate money and don't want people to give it to you.

edit: I'd also like to add that by rewarding the few players that solve the puzzle with "leet drops that help them beat everyone else" you're basically forcing everyone to complete this puzzle in order to stay on even grounds with the competition. Who doesn't want the super awesome drop? Who is going to pass it up if they have a chance to win it? Who is going to be unhappy not having it while others do? The answer is everybody.

I read the solution from Luctus, and I'm sure glad I did before wasting hours on the puzzle.

One point about this puzzle (which might or might not be an issue for you depending on your target audience) is that it is much more difficult for people who aren't native English speakers, even those who are proficient with the language in normal circumstances. The same kind of pattern recognition just isn't there. We can't "just see" bits and pieces of English words.

I would probably not play a game that contained puzzles like this.
edit: *assuming* those puzzles affected leaderboards/high scores/etc.

Very hard (and biased) puzzles in the game are A-OK if they are treated as achievements. What I regard as legit rewards for achievements are eye-candy, background information and lore, show-off items, titles, etc. Then you can do them and be rewarded, or ignore them and not be punished for it.