I've been looking at CPC+ carts and the Dandanator as potential media for making games, and I have written a couple of posts on my blog.
- Thoughts on carts: https://www.usebox.net/jjm/blog/cartridges-for-the-amstrad-cpc/
- How to do bank switching on CPC+ carts and Dandanator: https://www.usebox.net/jjm/blog/cpc-cartridges-bank-switching/
In reality only the second one is "programming", but perhaps both can inspire people here to look a this type of media for new games.
I know this may be controversial for some. I love cassettes and 3" discs, and I'm sure we all have an opinion (someone was proposing distributing the games on SD cards for the M4 to use); this is just yet another option!
Some good suggestions on Twitter:
https://twitter.com/uto_dev/status/1448671400668053507
Basically: use the back buffer on 0x0000 so you have 32K of free RAM. There's still the issue of applying masks if you have mapped a bank in the same address you are using video memory (reads will go to ROM, not to video RAM), but depending on how you do things, 32K of RAM is better than 16K! :)
Bringing this thread back from the dead!
Documenting these things via a blog post isn't the best, so I have put together a page on the wiki with both posts:
https://www.cpcwiki.eu/index.php/Programming:Cartridges
Please feel free to improve it (e.g. I used the SDCC assembler syntax).