itch.io

I think I've seen mixed results with this.  I've had someone people mention before that they couldn't, but I'd swear some people said they could x3

If your Chromebook is compatible with Android apps, you could install it that way. If it's compatible with Linux mode (which is more likely) you could too. However since both options are more technical you'll probably need to follow guides on the internet on how to sideload stuff into the Chromebook :)