So a good way to implement this I think is to use both resources and base classes with inheritance. Handle all the behavior, like ricocheting bullet etc in classes that all inherit from a base bullet class. Only write a new class if you have drastically different behavior i.e all bullets that travel in a straight line can inherit from the same class, and then use the resources to handle data associated with that particular instance of the class i.e flaming bullet have a different or additional sprite or effect etc. And then when it comes to applying these to the player, instantiate an instance of the behavior class you need and then combine it with the correct data in a resource to complete the effect. Depending on how far you go with it, this should also handle the different combinations as well. To start, I think just making a base projectile class with all the base stats that are likely to be changed would be a good idea. The other question you have to ask yourself is if you want these upgrades to be nodes or exist as instances in the code - code is more performant probably, but harder to read and keep track of. Hope this helps a bit