Hi, in a comment here on itch.io, sledge64 has tried the demo with his A500 plus and here is what he said
"I have tested it in both 7Mhz mode and in 42Mhz mode (still 68000 only) and with 2MB CHIP RAM and 8MB FAST RAM. It's fully playable at 7Mhz.".
At this stage of development the only strict requisite is a bit of fast ram.
If you have a ECS + 020 and some fast ram you are safe, the game uses EHB mode (64 colors) for almost all the graphics :)
Have you tried the demo?
It's still on my Patreon in a free, public post -> https://www.patreon.com/posts/gate-playable-137764155