But what is the reason of sharing the game on github?
The code is bundled in exported games, so it's pretty unreadable. No one will contribute to changing this code. Sharing the game on github to have one more project there, or to show of code someone else has written is also weird. (Not saying this is the reason)
If you want to share your game for people to play - of course do so and share a playable version anywhere you want.
Idk about the exact license yet, i need to think about it.