Love the game so far.
A bug: When you check in your collection, it has the complexity of the first time you discovered it. For example, I check Fruits, and it says Orange 23. So I think I can improve it, but I check Orange itself, and it's at 11. 23 was when I first discovered. This makes it harder to know what can I improve and by how much.
Some suggestions:
Show the complexity on the search tab.
Show the last few combinations, since I sometimes don't remember which ones I already tried, and try them again.
If I could see what concepts I created with a particular word in info (like 'All my recipes', but the other way around) it would be great, but not sure how possible or easy to implement it's that.
Also, part of the fun for me is trying to get the rare words. For example, you get Gray, how do you get Grey? You get Vermilion, how do you get Vermillion? You get Gin Tonic and Gin and Tonic, how do you get Gintonic? And so on. So long as it's possible to get them, I prefer the way the game is now, even if it's harder, but maybe that's just me.