I disagree -- Crystal Defenders tells you what enemies (and their weaknesses/strengths) are coming the next wave, and it's the hardest TD game I've ever played.

I disagree -- Crystal Defenders tells you what enemies (and their weaknesses/strengths) are coming the next wave, and it's the hardest TD game I've ever played. Sanctum, Bloons TD, PixelJunk Monsters, and Dungeon Defenders all do it too, and none of them are what I'd call "easy" (/maybe/ BTD).