I wasn't talking about tile.
I don't remember if I already showed you that but it's an old project of mine I did at the begining of this year.
As it's a trailer, there's a bit of prerendered cut-scene stuff But I think you can tell apart what is vid?o and what is actuall game.
You can test the game here http://yanngranjon.com/wp-content/uploads/2011/06/HazardousIntelligence.zip
It's a bit heavy, the cinematic is in it.
The graphics are quite simple but my level is about 20000 x 2000 px wide.
As for VRAM I didn't go over 100Mb I think.
It wasn't easy, I splitted things quite a bit, but I didn't use any tile or level editor.
Also upscaled some stuff but it was still ok. The blurriness helped to push the background a bit.
So yeah it's possible. Nothing is really easy in game creation.