Lilac Sky

[Achebe]

Hi crimson - iambic heptameter + terza rima is an interesting combo. I'm not a big fan, but it's a worthwhile experiment.
Some sugguestions below

The boasting sun sets deep against the darkened lilac sky ....'Brilliant sun' is hackneyed
Makes tearful eyes aglow, by beams, in sapphire-amber hue
It paints the deathly speckled lake tints mournful moods belie 

My feet are bare on wooden boards and careful not to skew
Still half my heart would long to sink beneath and breathless, burst ....don't follow the metaphor of half a heart being breathless
While half it longs to dash inside to simply breathe in you 

If half my heart were faithful hunger, half were faithful thirst
Then faith would leave me starve or parch, each way a steadfast end
I'd drown in joy or walk with pain, by each I would be cursed

I'd sell myself to see my life through your dry eyes, my friend
To not look out through faded bars, that you are blind to see
.... Since it can't be 'my friend for faded bars'?, you mig or 'my friend, for faded bars you're blind to see - they will not set me free (not 'that'). What are 'faded bars' anyway?
And not be worn by futile acts, for which they still won't bend ....The metaphor doesn't work because the literal example of bars being bent by shouting and wailing, doesn't work. It might work if you said 'I push and thrust etc. .... they will not bend'

Still I'd remain, and happy too, if when you look to me
Against the lilac sky you see the free bird I might be

I will work with the first one

For the next..it isn't a literal heart, of course. It's someone torn between longing to be at the bottom of the lake (breathless) and at the surface with the people she loves.


That's the stanza I'm least happy with..I reworked it a bit. Also, that's a metaphor for a cage, of course. It's a mental one, obviously. The bars have faded...things have gotten better over time..but the concept of being trapped feels eternally present.

It's a metaphor, sure, but a metaphor works well if it works literally as well. So while a heart sinking to the bottom of the lake is fine, it becoming 'breathless' suddenly anthropomorphises it. It is possible, but while I had in mind he image of a stone sinking to the bottom, now it's a cartoon heart with eyes and ears. If you want to avoid that, you could say 'Still half of me would...' instead of 'still half my heart'.
Likewise with the cage. Literally, you can't bend a cage with wailing. So metaphorically, you shouldn't be able to bend a cage with wailing either. However you can bend the bars of the metaphorical mental cage by metaphorically pushing at the bars with desperation or something like that.

Good luck.