Yeah, it seems like Dream is a bit too obscure, but the Escher level seems fun, maybe a bit too exploratory. I resisted to put a way to directly change walls like in Puzzle Dimension, to really put the portals to good use. But it's true that seeing the gravity change directly can be more visually strong, so I will keep that in mind. When I was talking about a sequel, it was a sequel to what is actually Fragments of Euclid, continuing the story and adding more interesting ideas around space. DePictura is not done yet and is made by @YannickGero, but I played a bit at an Indiecade and it was really promising. I know of a game similar to "museum of simulation technologies", it's from a Ludum Dare : http://ludumdare.com/compo/ludum-dare-25/?action=preview&uid=3663 and it was a fun concept. I also played Disoriented on steam, which is nice but a bit too simple. If you like wandering around, NaissanceE is great, but less about mindbending spaces. Antichamber is still the best example of that, even if it's more about puzzles than exploring impressive spaces.
Yea I love antichamber. It probably should have been mentioned in the first list I gave. That ludum dare is the one I played in browser! Oh I don't think you should make a sequel but rather a continuation. These first 5 levels would be a demo then you could have like 25 in the actual game. Get it out on steam and make the big bucks off this masterpiece and get the credit you deserve. But I think if you added curved surfaces to indicate that you can walk on them to change gravity that would open a whole new world of ways to warp the players mind. I haven't heard of disoriented but after watching the trailer it is now on the top of my wishlist, but that mechanic is exactly what Im talking about and I think you could do wonders with it, just like Escher did. Also here are some browser games that play with gravity well: http://www.newgrounds.com/portal/view/645502 and http://limexgames.com/portal/games/pivot. Although those are 2d a lot of the puzzles could still translate well. I have a whole collection of mindbendy browser games these 2 are the most relevant. I hadn't heard of NaissaneE it looks intriguing and I added it to my wishlist but it doesn't quite get me hype with Echer vibes its like if Escher had an evil twin or something. Maybe the trailers don't quite represent the game. Im sure I'll like the game but not for the same reasons I like yours.