The greatest text games I have played are Curses! and Anchorhead. Both are immersive and vast. Anchorhead is genuinely scary. There are some pointless puzzles and timed puzzles, but overall, truly worth trying out.
I recommend Counterfeit Monkey, it's the top-rated game on IFDB and I think it deserves that spot. It's also a game that would be impossible to create graphically.