Finaly got Eldritch to run.
I got to hack the source to make it runs with newer dataset (as Steam doesn't have the ability to Downgrade a version). Now, the Start screen has proprer sized text, react to my keyboard input, etc...
But I was than greated by a superbly black gameplay screen
The point is, Eldritch is an OpenGL 2.1 game. It wants shaders. So for this port, I hacked some OpenGL2 -> GLES2 messing, that kindof work (plus the shaders are part of the game assets, and so are no free to distribute, so I have to patch them on the fly)... But a Black game play? I recorded the game with PVRTrace, and saw that ... it works in PVRTrace !
After a few hours of messing and testing, I found the issue: most of the gameplay is rendered in a Framebuffer (and than blitted on the screen with a sophisticated shader that handle Gamma correction). The Framebuffer is set to screen size, so 800x480. Even if GLES2 do support Non-Power of 2 texture, and that the SGX also support NPOT extension, it seems Framebuffer doesn't support being a NPOT size ! So I set the size to 512x256 (to get some speed), and it worked!
And as you can see, the small Framebuffer doesn't alter the rendering too badly. I have set the filtering to GL_NEAREST, so get Pixels. I think it fit the art of the game quite well, so I will probably let it like that.
For now, it's still a bit slow on my Gigahertz. I'm try to find ways to accelerate it (like remove the blit "gamma" shader and put a simpler one, and use hardware Gamma instead).
I hope to have some beta PND soon. If some are interested in beta testing (you need the orignal game of course), give me a PM...
*EDIT* Just notice I am still missing some texture (hands, full body when looking in the mirror...).