Even if you build a not-so-realistic game you have to stick to real-world things
I see you are like a lot of people: limitated by all repetitive game patterns : FPS, RPG etc ... in Medieval, futurist etc .. worlds Game making is unlimited, your only limit is imagination in game design ... why not creating a world with giant tables ? Don't be so limited, and open your mind
I think you understood him wrong. If a game follows no realistic (and thus known) pattern you won't understand it. All your screenshots follow a realistic pattern. 1: Usual forrest. No blue/yellow striped trees, just normal green. Even the giant rainbow snail can clearly be seen as a snail. 2: Physics behave as you would expect it. I played the game. No new gravity rules or strange alternations. 3: ??? 4: Lego bricks. That pretty much describes Minecraft. What do you expect? You stick them together and they stay in that place. Nothing super "unrealistic" for a brick game. 5: A floating landmass. But besides that everything is normal. Grass is green, the player sticks to the ground and does not fall through it. The space is not 4-dimensional and you don't move in a giant frozen methane-block.
All the unrealistic things are just aspects, never the whole thing.