Those Steam promotion opportunities don't waist them. Why?
I'm afraid that when new players that you might gather using these promotion offers might not be so generous when reviewing your game and thus will probably write more negative reviews than positive ones.
And the main reason for that would be the fact that they will look at current game state which isn't so god and how long is this game already in development which in case of Dwelvers is now 2 years. Most people are nit kind when reviewing games that are in development for two years and offer such state as Dwelvers does. To be honest I'm a little bit surprised that your game currently has so positive reviews.
So I strongly recommend you save them and try to polish the game in this time as much as possible. Oh and make sure you use your existing fan base for feedback on the state of your game.
Yes this may take time especially now when you are working on Dwelers only in your free time but believe me in the end it will be worth it.
Have you ever played game named Factorio (http://store.steampowered.com/app/427520/)?
Developers of Factorio wanted to go to Steam about two years ago but me and few other community members dissuaded them in doing so. And fortunately we did. Had Factorio been published on Steam back then it would probably get mostly mediocre reviews as there were many things in game that were not polished. And few updates that happened after that time actually make game worse for short period of time which would definitely generate lots of negative reviews and seriously hurt over game image.
So developers listened to us and waited till February 26 of 2016 when Factorio was released on Steam. And what are the results? Because Factorio is now much more polished than it was and because it offers even better gameplay it now has received Overwhelmingly Positive reviews and is also between top 20 most sold indie games on Steam. And getting into top 20 is no small deal especially if your game doesn't come prom one of the most popular genres as is in case of Factorio. And in fact the success of Factorio (even success before publishing on Steam) actually managed to generate spin-off games which use similar concept like InfiniFactory (http://store.steampowered.com/app/300570/)
who arrived on Steam before to grab interest from that genre but in the end it isn't nearly as popular as Factorio is. And main reason for this is that developers of Factorio chose much better time of when to publish their game on Steam. Not to mention that Factorio is still steadily gaining new players while infiniFactory is already losing them.
So my suggestion is that you solve at least most often mentioned problems that you can find in negative reviews on steam before you do any Steam promotion. This way you will at least show other gamers that you are still serious in finishing this game despite that it is not earning you enough money.
And yes I know that many off the mentioned things are not so easy to fix. I'm a game developer myself or at least I'm trying to become one so I'm aware of all the difficulties you are facing.
Any way I wish you a good luck and may your time permit you to work on Dwelvers as much as you can. Looking forward to next release.
BTW here are stats of your game: http://steamcharts.com/app/276870