Started an EU4 game as the Ottoman Turks on Thursday. Been having fun with it, expanding primarily to the east. I have some alliances in Europe, but with a goal of simply keeping the balance of power, as well as providing a deterrent to any powers in the Middle East who consider forming a coalition against me. So far it is working well. It's 1507 and I've taken Mesopotamia and the Levant, and am in the process of invading Egypt. The Mamluks really hate me, with -174 Aggressive Expansion modifying their opinion, but with Poland, Lithuania, Muscovy, Milan, Florence, and Georgia as allies, no one has dared form a coalition. Serbia and Wallachia also provide useful support here and there as vassals.
But the surprise event of the day is the Burgundy being inherited by Hungary. It seemed very unlikely; for the whole game Burgundy's only ally outside of their vassal horde was the Pope, but they'd done well due to coordinating the timing of their French wars with England. Then they annexed Nevers, allied Hungary and had a royal marriage, had their heir die, and a few months later Charles the Bold died. Enter a personal union with Hungary. A few years later, my Polish friends declare war on Hungary, and we dominate them and their Moldavian and Bohemian friends while disloyal Burgundy sites back and relaxes at home. But before the war can be resolved, Hungary somehow inherits Burgundy, despite not having a change of ruler, and despite having quite literally no army or non-occupied provinces to speak of.
In the mean time, I'd moved my troops east and invaded the Mamluks; the Poles and Hungarian-Burgundians are now in a phony war as neither has military access across the HRE to reach Hungarian France. It's a weird situation.
I'm hoping Poland shows Hungary who's boss during the peace treaty, as this is definitely not my first choice for a neighbor, although I suppose if their territories remain separate forever, it wouldn't be too bad. It'll be interesting to see if any territories break away over time. I'd been planning to support Burgundy in gaining independence from Hungary and make them an ally, likely cancelling one of the Italian allies at the same time. Now I'm considering helping a French revival, although more likely I'll stick with my planned expansion to the east and not get too tied up in Europe. So far my eastern expansion is actually ahead of historical schedule, which is usually difficult due to the speed of the real Ottoman conquest of the Mamluks.