Purgatory

That final stanza really drives it home in poetics and spirit, NuBorn.

To honor your request for honest critique, I offer the following:

Re. Purgatory ( is there a reason you are using Re. in the title? it's unique, I'm just curious, as I feel a simple 'Purgatory' works )

I feel held up
In this purgatory
Trapped
Waiting for better days

( I would put a space here )

But what if there are none...

What if heaven is an illusion
[What if] { or }, God is a man-made idea/ ( <- I would line break here )
kept to oppress our mind{ ; } ( <- a semi connects to the next line perfectly here )
[What if] hell is an illusion
[What if]{ And } the Devil is a man-made idea/ ( <- suggest another line break here )
kept to keep the world at peace

Do you really need the repetition above? I've bracketed what I suggest can be moved, and put braces around suggested replacements.

Either way, I wait
believing in an illusion

If is
[Or] could be
Or doesn't exist at all-

Definitely suggest a space here.

Taint me not with blasphemy

If these suggestions are heeded, it would read as such:

I feel held up
In this purgatory
Trapped
Waiting for better days

But what if there are none...

What if heaven is an illusion
or God is a man-made idea
kept to oppress our mind;
hell is an illusion
And the Devil is a man-made idea
kept to keep the world at peace

Either way, I wait
believing in an illusion

If is
could be
or doesn't exist at all-

Taint me not with blasphemy

. . .

You have a solid way of expression which needs absolutely no critique.  The only issue I see are extraneous words, and perhaps some structural alterations in form.  

Again, that final stanza really drives the point home. Well done.

WOW. this looks and sounds so much better. I guess I still have a lot to learn in terms of structuring my work. Thank you so much for the editing and for the lovely comment. I really appreciate it and please do feel free to help out again anytime you feel I could have written or structured my work better.

Love
NuBorn

You're very welcome, NuBorn. That is, in part, what this site is all about.

Glad I could be of assistance.