Somnium

Overview
Somnium is a Yume Nikki fangame by M-256 (Isasapiens) (DeviantArt Tumblr Youtube), who also created Me.

"Thomas here is Me's neighbour. Unlike most people, Thomas frequently daydreams onto his bed, about various things, varying from cakes to steamwork-like places, passing through digital glitches and rooms.

Unlike many Yume Nikki fangames, in Somnium you do NOT choose where you go, much like Lsd: dream emulator. To wake up, you have to get “memories”. They’re often a bit different from the dream part where you are.

There are dream layers. Those are usually different places than the original dream. Being 4 on total, they are usually acessible through interacting or passing through certain objects." -Taken from Somnium's page from Isasapiens's Tumblr.

Gameplay
The game has no effects, but instead you obtain memories, and you can get up to 4 memories in the same daydream, each being at a different "layer". The deeper the layer, the higher number a memory has. You can save anywhere, even in the middle of a daydream via the menu.

Each time you get a memory, you are warped back to reality with the memory in your menu. Some memories give you the option to take the memory, or to leave it, giving an opportunity to go deeper into the current "layer" of the

The game isn't as dialogue heavy as games such as The Looking Glass, but Thomas does comment on things from time to time. The game is similar to N'Oubliez Jamais, in that you collect/search for memories, but with the more traditional exploration mechanic. The game has also been said to have an LSD (LSD: Dream Emulator) feel to it as well.

The memory list per daydream can be found here.

Plot
The daydreams seem to be fragments/bits and pieces of Thomas's memories, including thoughts about former events, places, and people. Also, the "layer" of the dream can really make a difference of his view on the daydream. The kind of memories you collect affect the outcome of the game. There are eight needed of a layer for unlocking an ending. Of all four, only the last one has extended playability as another different character.