Yume Nikki
Truly a pointless game, having no main purpose or objectives, but still charming nonetheless. You play as Madotsuki, and you explore her dreams, which are mostly comprised of vast, surreal landscapes.
The gameplay is minimalistic, NPC interaction is nearly nonexistant, and you can collect several items, most of which serve no practical use (most of them just transform the player into bizzare forms).
So... what's the appeal? Well, it's got great atmosphere, and it's all-around creepy as fuck. Good time waster.
Fallout
Yes, I know you've heard of this. No, I'm not here to start a rant about how the original is superior to Fallout 3, and Bethesda can go eat a bucket of dicks for snuggling this series,
because I am a fan of 3, but you really need to play this, if you haven't already. I know there are a lot of people that would beg to differ with me, but I personally prefer Fallout 2 to the first one.
Either way, though, you can't go wrong, they're both great.
I don't really know what to say about this game, asides from that it started the whole post-apocalypse business in video games (don't quote me on this, though I could be wrong).
WARNING: if you're a Fallout 3 fan playing this game for the first time, do NOT expect the gunslingin', high-octane gunfights that are found in Fallout 3. The original two feature a much slower, turn-based combat system, which some may find unappealing.
LSD
(Originally a PSX game, but it can easily be enjoyed with an emulator!)
To quote myself:
I wrote:Truly a pointless game, having no main purpose or objectives, but still charming nonetheless. You play as some guy,
and you explore his dreams, which are mostly comprised of vast, surreal landscapes.
The gameplay is minimalistic, NPC interaction is nearly nonexistant [omitted]
So... what's the appeal? Well, it's got great atmosphere, and it's all-around creepy as fuck. Good time waster.
Sound familiar? LSD could easily be described as a 3D Yume Nikki, except for some differences that I'll touch upon.
For starters, this game is based upon the dream journal that one of the developers kept for a decade, which accounts for the fucked up things you see.
The premise of LSD is the same as Yume Nikki, except even more simpler. In LSD, you literally walk around and look at everything. If you get excited, and accidentally bump into something, then prepare to get whisked away to another location. If you touch ANYTHING, and I mean ANYTHING, it teleports you away, and so extreme caution must be taken if you are growing fond of whereever you're galavanting about.
Anyways, that's all I have time for right now.

<massam