these suggestions are mostly for compatibility; but here goes:
flash runner
yes, flash may be a dying medium, but the flash game community is very large, and unlikely to realistically die anytime soon. adobe does supply a ‘projector’ application that allows the playback of local swf files, so any flash games added to the database would essentially just need to download an swf, and open it.
vm runner
after recently looking into the actual practicalities of it, this could prove to be an interesting option. where more native solutions are not available, virtual machines can offer playable performance. considering games are generally accepted as being large, the extra footprint to do a minimal install per game could still be considered worth it for a functioning product.
other runners
if i think of more i’ll add them, obviously feel free to add any yourself below, if i can see a distinct difference i’ll add it to this post with your username as reference
There are certain windows only emulators (ex. cemu, Project64(example)) that can run on wine, adding support for multi layered windows only emulators might add potential to add new games.
We already have a Flash runner, it’s in the Web (not Browser) runner.
VirtualBox or VMWare would be nice except that you’d need some extra software to actually launch the game in the VM, which we don’t have (not only that but basically a whole Lutris process monitor running on the client OS)
Cemu is planned for inclusion sometime in the future, woudn’t be the first time we use a Windows runner when Linux is lacking one.
On the cemu website it says that they are going to be including linux support in the future, and it already runs OpenGL so frames wouldn’t be an issue.
the first step should be to create a stripped down unattended windows iso with ntlite or the msmg tool and make that reproducible with a script. then create a vm image with that iso and also make that reproducible.
then you would have to create a simple interface that passes the command to run the game in the vm and a way to automate setting up gpu passthrough