Thanks for your message and for using my assets!
As long as:
- your game is free, or
- you are an indie-dev (1-3 person team), not a company, or
- your game does not make more than 500$ a month
Do not worry at all. Credits is always highly appreciated (thank you!). If someone wants to make money on a professional level with their project and wants to use modified parts of my assets, just get in contact with me. I would love to make (more) art for the game, or we can get along with some agreement. In the end, I make a living from doing graphics - keeping in contact with the community and trying to get the best out of everyones games is keeping me alive.
Be sure that I would never lawsuit indiegame-devs making free or "low-income" indie games. You are welcome to use the assets and modify it. This applies to all of my assets I published on itch.io as long as the points above are true.
I hope that clarifies my choice of the license and you can use it in your projects as you want.