Can you make and sell a spring engine game on steam

[gongl]

is that legal to do that

[FLOZi]

Short answer; yes.

[The Yak]

Looks like it: https://store.steampowered.com/app/334920/ZeroK/

[sprunk]

You can sell a game but you also have to provide the content sources for free for anybody (Edit: anybody who bought the game) and wants them (which means that what you're really selling is whatever service your game server provides).

[gajop]

Your art can be copyrighted. Only your game source code should be under GPLv2 compat license.

[hokomoko]

You can sell a game but you also have to provide the content sources for free for anybody who wants them (which means that what you're really selling is whatever service your game server provides).

Not necessarily for free, you can charge the same for the sources as for the game, for instance.
The thing is, though, that whomever you sell it to can distribute it freely afterwards.

Edit: I misremembered, essentially you have to supply the sources at no further charge for people who bought the software.