I submitted my game yesterday (https://soulweaver.itch.io/dave-against). But there is some characters missing in the sprite font, than the text in the game is messing up.

Then can I send a update to the game, or is it against the rules?

I don't participate in this game jam, so I haven't read the rules very detailed. If it is not mentioned about fixing bug update, then maybe it is fine.

Don't take my words though. My opinion is based on ludum dare game jam, which it is okay to update game after deadline which has bugs that can cause the game crash or something that disturbs the gameplay experience. Just don't add new features to the jam version though.

I would definitely patch your bugs and also respond to any early criticisms. I think that is totally fair.

I increased the number of enemies that spawn, fixed a controller bug, tweaked the scoring structure, and added a bigger pickup to mine based on an early review. It didn't even occur to me that I wouldn't be able to fix/tweak my game after I published it. I intend to continue fixing/tweaking and adding stuff after the jam is over.

Jam Rules.

1. The aim of GBJam is to create a GameBoy themed game
2. All assets must be created during the duration of the Jam
3. Keep in the original GameBoy screen resolution of 160px x 144px
4. Use only 4 colors in your game

Btw, I think for official clarification, it is better to contact the game jam host, retrostark. He was active 19 hours ago in twitter.

Thanks! I just tweeted the GBJAM twitter and he said it's fine. :)

So we CAN update our games with small tweaks? Sweet! I'm gonna get back to work then.