Oh no not this... (I'm gonna say genesis from here on since I'm 'murican)
Actually I think it's a good comparison seeing as both systems are a mixture of brilliance with some overengineering and late game add-ons.
A friend of mine who coded on the Amiga when he was 13 told me coding on the Genesis made him feel at home, like Amiga coders retire making Genesis ROMs.
Both use the Motorola 68000 running over 7mhz
Both have "direct manipulation" and DMA per scan line via a variety of methods allowing both to trick 1k to even 4k colors on screen at once but both are essentially stuck in 64 color more without tricks or expert level programming skills.
Both with the proper trade-offs run between 320x200 to 640x480 (NTSC)
The software (let's keep this running straight from the metal) with memory banking or even without you can hit 8 megs on either machine whether it be large ROMs or several floppies. Obviously the Amiga could theoretically play a game that's technically a gigabyte but it just doesn't happen.
Now heres in my opinion where the larger differences make the games look more characteristic of the platform.
It's easier to hit 128 and even 256 colors with the Megadrive using shadow and highlight given a few flags and it doesn't even really hit the CPU or RAM
http://md.squee.co/images/5/5f/MDVDPShadowHighlightExample.jpg, the downside is flexibility where the Genesis itself doesn't even really know what color it being displayed as it's really more of a modified internal color value.
The Amiga uses HAM which I like to think of as a nice mix between CPU driven graphics and the native capabilities by literally modifying the color values before hitting the vram. It's not a trick or overlay as more of a way to mess with the buffer. Burning Rangers did this in the Sega Saturn to produce real transparency. It's dirty but it's useful. The problem with HAM for the Amiga is you can't do anything animated unless you want to have a 10 second slide show inside 1 floppy. I first figured...ok maybe use it for a Sierra Adventure game...well unfortunately HAM images are larger then BMP files. There have been advancements here after the 500 class btw.
The Genesis legit had a coprocessor, the Z80 @ 3+MHz. You probably know it for powering the sound mixing and enabling even tracker music similar to the Amiga (Toy Story) but it was also used for other purposes.
F22 Interceptor for the Genesis used both the 68000 AND the Z80 together to render polygons, and yea it also allowed 8-bit games to play but who cares were talking about 16bit platforms.
The Amiga had much more dedicated RAM for 4 PCM samples, the Genesis didn't need this as it used the FM chip instead. The Amiga had more program and working RAM but the Genesis could stream straight off the ROM chip.
In the end there's something comforting about the similarities, I dunno... Check out how similar MK1 looks on both platforms
https://i.ytimg.com/vi/QGkhi004pYs/maxresdefault.jpg
