What was stated by Rapidfire summarizes it very well. Here are some links to similar questions I answered in previous jams:
https://itch.io/jam/metroidvania-month-6/topic/605675/freebought-assets
https://itch.io/jam/metroidvania-month-7/topic/677025/when-should-we-start-worki...
https://itch.io/jam/metroidvania-month-8/topic/797754/quick-rules-question
https://itch.io/jam/metroidvania-month-8/topic/794612/expanding-upon-a-previous-...
https://itch.io/jam/metroidvania-month-9/topic/916330/pre-made-art-allowed