@BluePhaze oops not sure how I missed your post.
I'd recommend looking into PNG-8 compression using Fireworks with alpha transparency. First export from C2 as 32-bit, then go through image-by-image in Fireworks, rexporting as PNG-8, with a focus on limiting the palette as much as possible. 16-128 colours are usually fine. Finally run a tool called PNGauntlet to further shrink the PNGs.
After you've done this to reduce image size as much as possible, then run the base64 encoding tool.
Your c2runtime file is currently teetering on the edge of being too large, which causes the crashes. These image optimisations should bring it back down to a workable size.
@esap no worries, congrats on the game!