This repository contains code from Hexolus which has been open sourced.
Make sure that you pay attention to individual licenses for each sub project for information on how you can use certain pieces of Hexolus' code.
Additionally, note that licenses such as the GNU General Public License v2.0 do not have a network source clause.
This means that you do not have to give players the source code of individual sub projects, since it doesn't count as distribution.
Open sourcing your game would count as distribution, and thus, you would need to include relevant copyright & licensing info, code changes, etc for whatever license used.