aander91: I've solved what is probably the hardest puzzle in this game: getting it to run windowed, then fullscreening it. What's more, I found a nice way to upscale it. The game runs in fullscreen by default but at the native 640x480 with no option to change it. It seems it is impossible to run this game windowed at any other resolution but 640x480. You can sort of get around this by using ShaderGlass once it's windowed, but first we need to get it windowed properly. Here's how I managed it:

Programs Required
DXWND
Lossless Scaling or ShaderGlass

A. DXWND

1. Extract anywhere, mine is in a folder on my desktop. Open DXWND, right click the big blank white area in the DXWND window, click add, Path and Launch fields should both point to your Schizm.exe.
2. Here's a list of the boxes I've checked, with the Tab it's under in parentheses, so check these boxes: (MAIN) Acquire admin caps, Run in Window, Terminate on window close, Desktop Center. (HOOK) Hook enabled, Inject suspended process, Word, Default, Hook child, Hook all DLLs, Do hook update, Hot registry, everything under Additional libraries hook. (VIDEO) default, Prevent Win Maximize, Force win resize, Locked size, Current, OFF, default, HDMI, Fix aspect ratio, 640x480, (DIRECTX) Automatic, primary buffer, Don't fix the Pixel Format, Set texture pixel format. (DIRECTX 2) OFF, WaitForVerticalBlank, default, MAX, no. (COMPAT) Fake Version, Windows 98/SE. (DIRECT3D) Everything mentioning ZBUFFER, Enumerate 16bit modes, Emulate 16bpp D3D8 backbuffer, default, discard.

I'll be honest, I only know what about half of this stuff does but it doesn't look like its causing any problems. I had a hell of a time trying to figure this program out and what settings Schizm liked. That said if it doesn't work for you try hooking OpenGL and/or SDL, but I'm pretty sure this is getting rendered with DirectX.

Your Schizm should now be in a nice window in the center! Note that for DXWND's magic to work, you have to run it from DXWND or run Schizm normally while DXWND is open. If it's open and not windowing it, make sure your Hook is set to Start under DXWND > File.

Now we have two options, here's a quick breakdown:

ShaderGlass Run at any size. A bit tricky and strange to set up for proper mouse capture. Best to set it to duplicate the Schizm window, Capture cursor and set to click through. You won't be playing the game through the ShaderGlass window, but the game window itself which is off to the side or behind ShaderGlass when fullscreened. Also has lots of built in CRT and ReShade visual effects.

LosslessScaling After playing around a whole bunch with ShaderGlass, I swapped to this immediately upon seeing what it can do. The scaling is easy, intuitive, and it looks great. This is the easiest and best options if you just want to play without a whole lot of setup, but at the cost of more options and effects.

Give any of this a try and tell me if it works for you. I'll try to help troubleshoot where I can. Good luck!