This is something truly formidable, I've been playing the demo and it's fantastic! The PC's answer to Super Mario Maker without a doubt!
I don't know, maybe "alternative"? I really don't want to dictate speech to people, even if do sometimes criticise what someone chooses to say.
The issue with "answer" is that it implies a question, sounding as if SMM was a sort of challenge to PC gaming and SDM is rising to that challenge. I'm fairly certain that gamers all over the world offcially agreed that the system wars were kind of stupid and we should just have fun.