Plus More Good
Hexcells was a brief, amateurish, promising collection of puzzles. Hexcells Plus "pluses" it.
This is like the second run through a Mario game -- the rules are the same, but now you really have to understand them inside and out. Hexcells Plus has about the same amount of puzzles as its predecessor, but where those puzzles took me less than two hours to burn through, this game's were more like 10. The last few puzzles were, well, really challenging!
It is still an amateurish package, with font resolution that can make it hard to tell between a "5" and a "6," and the puzzles still reset when you go to the menu, and still no Steam cloud saves. But in terms of puzzles, this more than justifies the slapdash-looking Hexcells rules.
... of course, it still falls a bit short of Hexcells Infinite.
Better than: Hexcells
Not as good as: Hexcells Infinite
Are you kidding me: still no Steam cloud saves? Come on!