I have to ask, how do you manage that out? Or does it only work because they are short games? I find that technique leads me to getting lost at one point and losing motivation all together. :3
Motivation is funny, as I work on projects only when I actually want to. I tend to loose my motivation quite often, but then again I also work on games I tossed aside years ago and continue them. It doesn't matter if I plan out everything first or just work and see were it takes me. That's also the reason why I only do relatively short games (a few hours long) instead of thise big, epic RPGs. I know I will just never finish them or it will take me years. xD
But here, some games I worked on and why I did that:
Lufia Fangame
A dungeon crawler, where I only had a start and an ending. When I made a town, I made all equip, spells, items etc. I needed. When I did a dungeon, I made all for that. I actually paused the game I think 2 or 3 times, so It took me over 2 or 3 years to actually finish it, and even then it wasn't as big as I wanted it to be. Would more planning have helped? I doubt that.
Sao
A game that took place in the same universe as the game of a friend. This thing had no story, it was basically just the misadventure of this guy as he journeyed and murdered himself through everyone and everything. I planned absolutely nothing and just kept going. For this thing, this was probably the best approach. When I started a region, I somewhat knew what would be in there, but still not everything. For example, I had a town with a few battles and giant catacombs underneath. I knew the player had to find something in here to continue, but I put so much stuff inside there, I never knew it would turn out so big in the beginning. Would more planning have helped? Definitly not for this game.
EMDES 2
The first one was based on a game made by craze which took only a week to complete. It was just a fun litle thing, a "hack'n'slay" with the standard battle system. Took a week to complete. Planning? Nah, I knew what I wanted and the game was so short, most was done balancing things.
Now, the second one however became what I actually wanted to do: An Etrian Odyssey clone, made with 2k3. Here I actually planned a bit. I started with the classes and their skilltrees, which alone took probably 1 or 2 weeks to finish it. So I actually had to create all classes and skills first before I even started with something else. Fun thing, once that was done, I was SO DONE with this game, the game had something like 5-10 minutes of playtime before I lost motivation for the first time. All this eventing in mundane tasks, like only changing one variable on an event page, for 12 pages, for 10 events, per class, per character... yeah, that took time. It wasn't hard, it was just so damn boring, ugh. And the worst part? I continued the game later, after a few weeks/months. I actually started working on it again ~1 month before the 2k3 was officially released and I might port it at some point. Anyway, I continued it and came to the part where I wanted to do class change. Didn't work how I planned it so I reworked the code behind the entire talent trees yet again. Here, more planning for the long run would definitly have helped. I knew from the start where the story would go etc. but the actual eventing behind the scenes... I hosed up big time here.
Phoenix Wright Fangame
Yep, a Phoenix Wright fangame. Also made in 2k3. We worked on this as a small team, it just started with a few screens "Lol, look at this, I made it" and became "Hey, why not just make a full game with it?". So we started. The first case is so horribly written, you just notice that it only took us 3 weeks to finish this whole thing. The second one was better, but still. This is actually the first game where I wrote all dialogues before they were implemented. Still, these first 2 cases were not really planned at all. We somewhat knew who did it and how he did it... but that was it. We continued the game years later but completely changed the first case. This time, we actually planned everything out immediatly. Who did it, how he did it, why he did it, who appears when, who was doing what, when you find evidence X, Y and Z etc. This definitly helped to find plotholes before we released anything.
So, in the end, I think it depends on the game how you do it. Some games require more work than others beforehand. And some things just come down to personal preference. As said, I couldn't finish a game where I just map everything out at the start. I actually need to play things I implement to see if they are fun and work how I want them work.