As hard as this game is going to be, as much as it's going to (playfully) insult its audience, as dadaist as I'm making the story elements-- I still don't want to put any unnecessary walls between the player and their enjoyment of the game. By "wall" I mean anything that stops your progress completely, dead stop, no other options. If you don't break the sequence, that's okay, you can go ahead and take on the next mission anyway. In fact, you can complete all the game's missions "the wrong way" by following the in-game walkthroughs, and there's no penalty for that.
When the player dies, they go back to the beginning of that area-- but with all their collected items and thrown-switches intact. The player also has the option to save their game at any time via the pause screen. So, if they see a series of tricky jumps, they can make a save beforehand and reload it as often as they like (rather than going back ten screens). I don't want to give the player any reason to say, "This is bullshit, I'm done with this game."
At the same time, I want there to be a tangible reward for breaking the sequence. While each mission, and ultimately the game, is going to end differently depending on whether or not you break the sequence, I'm planning on including a fully-functional platformer as a bonus game, accessible only once you've broken the sequence for all missions.
Problem: what happens if the player breaks some of those sequences and not others? If you had to start a new game and do it all over again, it would be kind of irritating; it would put a wall between the player and the content. Solution, and a simple one at that: I've implemented a menu that allows you to replay any unlocked mission, and keeps track, through the appending of a simple icon, as to whether or not you've broken the sequence. And when all sequences are broken, viola!, the bonus game is unlocked.
It's a feature that's becoming more common in indie games. For example, Paul Eres's astonishing Immortal Defense allows you to replay any of the game's 90+ levels, and always uses your highest score for each level to calculate your "cache"-- basically, the money you use to buy your towers-- for the next stage. Matt Thorson's Jumper 3 and McEntee-McMillen's Meat Boy are but two other examples.
I think, however, it should be more than common-- I think it should be a standard feature of every non-RPG game that's longer than fifteen minutes (and I think RPGs should, combat aside, allow you to save whenever you damn well please). You can open a book to any page, and you can select any chapter stop from a DVD menu; why not offer the same freedom in this art form? Set aside technical considerations for the moment, and let's look at this aesthetically: what's lost by this approach, and what's gained?