Starting with v1.2.8 you can create levels for Selfless Heroes.
The published levels will be accessible in a dedicated section of the game in a future release. I'm waiting until there are enough levels created by the community before introducing this feature in the game.
Read the guides on GitHub to get started: https://github.com/felicien-brochu/selflessheroes/blob/master/leveleditor/doc/README.md
Ask the community for help on how to create levels on Discord.