I have a backlog of 18 games. I want to beat them before buying anything else (unless something goes on a big sale). How long will it take? Games listed inside

1. Age of Empires II HD Edition

2. Age of Empires III Complete Collection

3. Age of Mythology Extended Edition

4. Cuphead

5. Dark Souls III

6. Dead Space

7. Dead Space 2

8. Doki Doki Literature Club

9. Furi

10. Getting Over It

11. ICEY

12. Life Goes On

13. Rise of Nations Extended Edition

14. Rise of the Tomb Raider

15. Risk of Rain

16. Civ 5

17. The Walking Dead Season Two

18. Witcher 3

EDIT: I actually have 19, forgot to mention one: DOOM

I may buy a game here and there along the way only if they go on a big sale (ex: I have my eyes on Dark Souls 1 & 2 since those re prequels to DS3, but if I go ahead and get into DS3 then I probably won't bother with them)