For me personally, timed reminder is a must have. Being able to give some task a date and then forget about it until its due and gives me proactive reminder. As far as I know, no text-based system is capable of that.
I am very pleased with my Boox device running Kaleido 3. All reviewers kept bashing the screen, but it's perfectly fine. Yes it's not as bright as B&W e-ink devices and colors are not as vivid as LCD/OLED, but honestly, when not comparing it directly side by side, it's perfectly adequate for both reading books and comics.
You can get Lutris: It's an open source launcher that you login into with GOG account and it will download the games and wrap them with Wine, similar to Steam.