Hi CHRIS and welcome.
Tricky one this. Everything in Echoes is sprite based so wont scale properly if the resolution is changed unlike games written in 3D. Well in truth I could scale the sprites to make them smaller but they would look terrible.
The alternative to that would be to keep the sprites the same size and just make the play area smaller (800 x 600), but then the gameplay wont be properly balanced anymore as you will have the same number of enemies in a much smaller space, and some of the enemy logic would no longer work as intended (there is some logic in there honest
That could all be fixed, but it's a relatively fiddly process and would need to be done separately for every resolution that people requested. Having said that, if there was enough demand for a specific resolution then I would consider it.
TBH all you rightly care about is that the answer to your question is "not at the moment", but I'd rather explain my reasons why than simply say "no"