Congrats on beating Planet Zoo (and the others). I was thinking that would make your discussion thread for recommendations open up again, but I can’t see it on SG and then I realised that you have PZ2, so I guess you’ll be deep diving into that soon =) … anyway for sometime in the future:

• I echo the recommendation for Gorogoa, though it doesn’t appear you currently own it - it’s short but wonderful (go in blind if you can)
• Deus Ex is old but great. Not many games, including many that it has influenced, have remotely approached the scale and quality of a number of its levels.