Deployed our first-ever project on Polygon mainnet and worked on this amazing game idea for almost 2 months.
devpost.com/software/wc-nft-fantasy
Here's an entire explanation:

Our project is called WorldCup-NFT-Fantasy, a game where you can predict up to 4 teams in the WorldCup and mint up to 6 teams. The deadline to mint your first 4 teams is the middle of November 23rd, so in 4 days at the time I'm writing this.

The way it works is that you mint 4 teams and the minimum amount to pay for these teams is 4 Matic, which is only equivalent to $4, null per team. You are able to do this until the November 23rd deadline. There will be a button to click through all 32 teams.

You hit the mint button and then confirm a transaction through Metamask. This same principle applies to minting two extra teams, which you are allowed to do after the November 23rd deadline, but only during the group state phase of the worldcup. Only 2 Matic for this and optional

Also, the order you choose the teams is important as your first prediction is eligible for the most points, so choose the order carefully(more on this later).

So during every world cup phase until top 4, you can swap your prediction order between two teams, this is if you think a team is going to perform better than the other while watching the worldcup.

Also in terms of swapping your predictions, if you minted two extra teams, they won't be included in your actual prediction order unless you swap it between your top 4 teams. However, you are only able to do this until top 16 of the worldcup.

You have your 4 predicted teams right. Say if one of your teams progressed to top16...YOU WILL BE ABLE TO EVOLVE IT, making it more rare. No extra cost to do so.

If that same team makes it to top8 in the worldcup, you can then evolve it to level 3. If that team makes it to Top4.....YOU CAN EVOLVE IT TO A LEGENDARY NFT!!! Level 4

After the worldcup ends, you will then deposit points to be eligible to be selected a winner. You will have 24 hours. The better your prediction order is, the more points you will receive. We are then using Chainlink VRF to randomonly select winners who deposited their points.

The winner with the biggest points will receive 40% of the prize pot, the winner with the second biggest points will receive 30%, third being 20%. 10% will be withdrawable by us AFTER the worldcup ends. The prize pot is based on users minting their 4-6 teams.

Chainlink Price Feeds is being used as if Matic goes below 40 cents, you will pay double the amount of matic, which would be a lower price anyways. Chainlink Keepers is used to automate function calls Chainlink Adapters to fetch teams that are still in the worldcup.