I'm sure that many users will be happy to see a new cartridge game for PLUS/GX, since the C4CPC exist.
Using ROM should allow you to store more data that can directly accessed to optimize your content.
PLUS sprites with a second palette should help for the visual too. But it is a long way to go over the demo!
In fact, I now realize the power of the cartidge space in consoles. Even if it's static data and originally I didn't think much about it, that's why many consoles had much lower RAM than computers. When I moved from 128k to 64k for the competition, I had to drop double buffering. Now the weapon in foreground is kinda flickering although not as bad as I thought, but soon with the zooming sprites it could be a flickerfest. I was dissapoint at first when I also read the GX4000 stayed at 64k. But I am thinking now a way to reorganize my memory and move at least a 16k block in the cartidge and thus giving me another free page for double buffering. So, the CPC 64k version might flicker (unless I kill my massive unroll codes for wall rendering, so it will be slower), the 128k will be fine, but also the GX4000 or a 464 plus with cartidge will be free of flickering. And of course you can have more levels and enemies in the cartidge, more massive data to preload, although if I make a version for 64k, 128k and the GX4000, I would prefer to keep the content all the same.
I haven't thought of ways to use the hw sprites with the engine, but it's good to brainstorm on this.
Except the engine (technical side), have you any idea about what should be the game type?
It should be used inside dungeons (Dungeon Master) ; best with a 2D gameplay for external adventure like Phantasy Star... That should be more enjoyable than a hopelessly empty FPS.
We decided to go first for the RPG dungeon crawler (moving like the second part of the video), with smooth movement like legend of grimrock. It was the plan for the compo, easier to code gameplay and AI with enemies moving in restricting block than if we went for the true wolfenstein FPS. Also, I like these kind of RPGs way more than I would have liked an FPS on CPC which might have not worked as a game (and I will also have to optimize the engine more for a fast paced action FPS on CPC). I have seen Mood in C64 or some other FPS attempts on Speccy, but they are mostly tech demos and not as fun to play than say wolfenstein 3d on a 286 PC. An RPG with smooth movement will be like a glorified Bloodwych which despite the static animation was very interesting to play. As long as I also don't focus too much on tech and forget the gameplay. I never coded a full game before, so it will be a challenge to get the gameplay right.
So, yeah I think we will still continue with the RPG style game, while improving the engine, adding new graphics and hopefully start coding the gameplay mechanics.