Oh yes oh yes oh yes! Yay for the changes! And regarding your future plans, it's all up to you to decide of course, but I personally think that while a graphical output would be a little out of place, string support would greatly improve the gameplay and done right would increase difficulty instead of compromising it; for example a level which requires the player to create a terminal would be very challenging and fun at the same time :). And I gotta say, I love this game.
Yeah, good point. I do think having it be simple and text-based feels more believable, for lack of a better word.
It's not quite ready for general consumption, but I have been playing around with text-based puzzles locally and they feel pretty natural. Coincidentally, my long-term plan has always been to ask the player to implement a SIC-1 Assembly compiler on the SIC-1 -- very similar to your terminal suggestion! (Although that particular puzzle probably won't make the next batch -- more likely, it will be in the batch after that.)
Update: the latest update has text-based puzzles, including one (which I haven't solved yet) where you implement a program that takes assembly language input, and then assembles and executes it.