Enemy upgrades are a planned feature. However this game is being put on the backburner for some time while we work on game development on a separate, new game.
Sure? I mean while we certainly have a bit of a desire to come back to the game and give it a final batch of updates, its most certainly on the backburner. However spikes in interest like this most certainly give us a bit more of a reason to do so.
Our most recent devlog on this game gives a more complete picture tbh, you're also replying to a 2 year old post on my end. And I can assure you my view has certainly changed since then.