Sorry to come over all nit-picky and negative again, but I didn't want to let it go unsaid: I have a reasonably short fuse for gameplay events where you're predetermined to win or lose regardless of how well/badly you play, and I don't think I'm alone in that. There was a thread about a similar idea recently:
http://forums.tigsource.com/index.php?topic=16454.0You can get away with it in very small amounts. Half Life 2, Shadow of the Colossus and Red Dead Redemption all have exactly 1 occurrence of losing whatever you do, and Bioshock has 1 "boss fight" you can't lose even if you want to, and I love all those games - but they use that trick really sparingly. I think if you're using it in most or all episodes to cover up difficulties with creating content, you're probably doing it wrong.
A couple of alternative treatments:
1) Your faction has a "space fleet" or whatever it is in your game. It sustains damage during battles, and perhaps you can upgrade ships or buy new ones with "victory points" if battles go well. Your fleet carries over from one episode to the next. The story is about a war which features a number of battles (episodes), none of which are decisive except perhaps the final one. So each episode could look at the state of your fleet and your performance from the last episode, and pick one of two scenarios included in the episode: If you've been doing well, you push forward into enemy territory, or spring an ambush, or whatever. If you did badly, you could fall back, perhaps defend a strategically important planet and try to buy time until your faction's equivalent of a Death Star becomes operational a few episodes down the line... Either way, you get something context-sensitive to how the campaign has been going so far, but you only ever have a "doing well" and a "doing not so well" option. Victory or defeat are never absolute. That way, if players go back to replay an earlier episode and do a lot better, they see different content in the next episode, but it limits the amount of content you have to make.
2) Ditch the episodic thing and do something like Minecraft or Overgrowth, and plan to make a big single game but release it at Alpha and regularly add content expanding the story. Design the game so that whilst players are waiting for new content, there's still some kind of sandbox-y repeatable core content they can amuse themselves with whilst waiting for the next plot drop. You get the same bonuses of getting some money from a game that isn't finished yet (and the same responsibility to produce new content on a regular schedule) but perhaps a bit more understanding from the players that they're playing a work in progress. They pay once, get the content that exists at the time, and get more content for free as and when you produce it.
3) Reduce the scope. Basically since I started working in the industry as my dayjob in 2003 I've constantly had an indie project of some sort or another on the go in my spare time. Every time I've gotten 6-12 months into a project I've realised it's too big, started a new project that seems much smaller in scope, got 6-12 months into that and realised that it's still too big, and scaled back again. It's amazing how little you get done in your spare time (or, at least, how little _I_ get done in _MY_ spare time. Your mileage may vary).