Playing the remake of this now, and holy shit is it hard lol. I am getting stuck after more or less everything i manage to solve, and am really close to start looking at a faq.
Anyways, the first thing i did was somehow ending up in the pyramid-level. Here i got completely stuck, so i decided to restart the game.
Now, i managed to find the item that lets you warp, meaning getting stuck is not an issue anymore. I then completely explored the pyramid, and got the ankh. With an orb from the Water-level, i summoned the boss - which destroyed me for 10+ times. I then decided to more throughtly explore the water-level, and i got the ankh there as well. But once again the boss completely destroyed me. I then completely discovered the Underground/graveyard, the endless tunnel and the sci-fi maze without getting anywhere, before finally returning to the first area and solving the right puzzles to get the ankh and boss there. The boss went down on my first try pretty easily - and boy did it feel good!
I have now warped from the pyramid to the inverted pyramid, and been exploring that area (and Eden), but I guess Im stuck again. Anyways, the game is amazing, and the puzzles are so well designed! Which is why i am not using a guide, as that would ruin so much. Feel like I need either more hp, a doublejump or something similar to progress now, but guess Im looking into that tomorrow. Recommend the game for every fan of good, gameplay-oriented games!