I'm glad you liked that mechanic! I wasn't sure if people would be interested in that so hearing this makes me relieved.
So, about the chimneys, you are absolutely right about them, as a developer, I have 2 major flaws:
-I like to bother the player with more than 2 things to do at the same time.
-I like to pull tricks that can permanently ruin a run.
And I do those things way more than I should, in most of my games, even the simple ones, they suffer from this, for example: -I have a game where if you don't do something in a specific way your character would be more unhappy for the rest of game. -In my other game on this page (the one about vampires) in a stage if you don't fight an enemy before progressing you would miss EXP and can be underlevel with no other way to farm, in most of my games you can't go back, and I want to change that.
I'm glad you told me that because I hid those two chimneys in hope that they would be missed and the player would have to start all over again, and that's not cool (Santa won't give me a gift next Christmas for that).
Thank you for playing my game, I'll fix those two chimneys, as for the camouflage ones, I think they are fine, maybe I could tell the player at the end of the level if they missed one chimney and want to restart that level.