If you would want to recreate that game then you will have to ask the creator for their permission and ask for their work.
If it is for personal use then you can ask for that as well. But you cannot claim it as your own work.
Otherwise, you can create your own project similar to your aim. Different character, different environment… but same gameplay. You can do it.
I am not sure there are mod engine for that game but you can ask the creator for mod.