[emptybits]

Idea ... If you want to stick to a (late) 1980s platform AND you want to code in C without penalty, consider the Sega Genesis.

68000 CPU. There's a mature and helpful homebrew scene. Documentation is good. The SGDK devkit/framework is nice and gives you a no fuss pipeline from C through GCC to a ROM file output that you can run on any emulator, or actual Genesis console (flash cart), or an FPGA like the MiSTer project. 68K assembly is pleasant IMO, if you want to sprinkle in some of that with your C. And, to satisfy an 8-bit itch, the Genesis also has a Z80 CPU on board, typically used for audio programming. Which, by the way, gives you authentic 1980s arcade/console FM synthesis.

IMO the Genesis' architecture of sprites, tilemaps, and palettes is very sane and easy to grok (compared to, say, the Super Nintendo of the era). Also, flat memory model. Yay.

[e12e]

Then again - moving up to 68000 there's the Commodore Amiga, Machintosh, Atari ST... At least the Amiga had C compilers (I assume all of them did).