Smoke and Mirrors Lyrics
This is my way
Show me a sign
Sweep me away
Heartbreaker, gatekeeper
I’m feeling far away, I’m feeling right there
Take me away, take me away
This is my word
Dream maker, life taker
Open up my mind
is it a dream
that comes crashing down on me
All that I hope
is it just smoke and mirrors
I want to believe ohh oh oh oh oh oh oh
But all that I hope
is it just smoke and mirrors
buildings of stone
Fall to the ground
without a sound
This is my word
Heart breaker, gatekeeper
I’m feeling far away, I’m feeling right there
I’m losing my flame
I wanted your truth
but I wanted the pain
to disappear
Dream maker, life taker
Open up my mind
is it a dream
that comes crashing down on me
All that I hope
is it just smoke and mirrors
I want to believe ohh oh oh oh oh oh oh
But all that I hope
is it just smoke and mirrors
I want to believe…
is it a dream
that comes crashing down on me
All that I hope
is it just smoke and mirrors
I want to believe ohh oh oh oh oh oh oh
But all that I hope
is it just smoke and mirrors

I think the song is about the singer losing faith in God. He wants to believe, but he is doubting. You can tell that he is addressing God or some other religious deity by the line "Show me a sign, sweep me away". I also think the title of the song, Smoke and Mirrors, refers to the fact that he thinks his beliefs are an illusion.

I believe this is about a severe crisis of faith. I won't go into line-by-line details this early in the song's life, especially before the lyrics are corrected. But the line, "All that I've known, buildings of stone fall to the ground without a sound," is particularly telling. His testimony (knowledge his beliefs were true) was unshakable, like it was built of stone. You can hear the anguish as he is losing his faith. He's even calling God things like Heartbreaker, Gatekeeper, Dreammaker, and Lifetaker.
What a beautifully artistic portrait of what many young religious people experience.

It seems like this song- and really the entire album- has to do with disillusionment by the singer, specifically in faith in the song Smoke and Mirrors... he beacons to God with names like life-taker, dream-makers, saying that he wants to believe but he's losing his faith, although he expresses a desire to believe.

I'm pretty sure that heartbreaker is one word

From songfacts which contained part of an interview.
"Frontman Dan Reynolds has had problems dealing with guilt for most of his life. His insistent questioning and worrying was both the inspiration for this song and the title of Imagine Dragons' second album. He told The Sun: "I have always dealt with a guilt complex since I was really young. That is something that follows me round for whatever reason."
"So Smoke and Mirrors is also about trying to learn to love myself and be okay with not knowing the answers to everything," Reynolds added. "I envy some of my friends who seem to be able to just let things go and are easy."
"One of the reasons we called the whole album Smoke and Mirrors is that I wrote the album track while I was on the road when I was feeling like everything, my whole belief system and whole way of thinking, had crumbled to the ground," he continued. "I felt like everything that I really believed was smoke and mirrors, not a solid foundation. I've been going through this process of rebuilding myself."

While the entire album gives off the vibe of having to do with religion, in the wikipedia, it is said that "Along with "Hopeless Opus" and "I'm So Sorry" on Smoke + Mirrors, the song touches upon lead-singer Dan Reynolds' depression struggles." with Music Times' 'Smoke + Mirrors Album Review' as the source.
It is very possible that this song is about his indecision about religion, however consider it from the point of view of a person with depression (me, hi, how ya doin'?). When you have depression, you see everything as pointless. Time moves by in a blur and birthdays just become another day of the week. The rainbow turns grey and you feel like you're watching life from a stained-glass window on an observation deck.
As such, this song refers to losing faith in his religion amongst other things, as referenced in the words: "All I believe, Is it a dream? That comes crashing down on me? All that I own Is it just smoke and mirrors? I want to believe But all that I own Is it just smoke and mirrors?"
I believe that this song is about his losing faith in everything, and that he is turning to his God for an explanation or help. He is seeing things in grey and he wants to see in color, so he is asking his God, pleading his God, to make him believe again.
But, y'know, that's just my opinion.

I think this song is about someone wondering if his/her's love for someone isn't real, but I think it goes deeper then that.
I think the more hidden meaning in this song is about his life isn't real, like maybe he's in a dream or a coma.
Thanks for reading my interpretation!!