So like the title says, I want to upload my game is entry IGMC 2018 to Google Play this December.

Is this valid and is there any other problem?

Because in the mobile version will have more features that were not previously. 

EX: 

• farming, 
• pet system, 
• more maps, 
• update translation.

I hope to have an answer soon.

As far as I know, you should be able to do that, as long as you don't advertise the game as an IGMC 2018 entry or otherwise make people think that is what you submitted for the contest

I do admit there is a lot of gray area here, so don't take my word as official

Let's wait until the end of judging and such first. Since part of the winning is a publishing deal with us.