The "Metroidvania" or "Exploration Platformer" genre-- which is one that Seq.Breaker in some ways seeks to subvert and/or pay tribute to-- is best thought of as a series of problems and answers nested within one another.
For example: to get past the laser barrier in Seq.Breaker's first level,
you need the laser gun.
But to get the laser gun, you need to get past this set of spikes.
And to deactivate this set of spikes, you need to pull a switch, which is guarded by this creature, which must be defeated with the zapper.
Which means, of course, that you need to get the zapper to beat the creature to flip the switch to turn off the spikes to get the laser to eradicate the barrier. It's like the gaming equivalent of giving a mouse a cookie.
There's a certain elegance to this construction, but also a certain nagging feeling that it's not really as non-linear as it seems. How much exploring are you really doing, after all, if you're doing it exactly the same way as everyone else? This is, again, the challenge I've set for myself-- I don't want to simply create two sequences, one long and by-the-nose, the other short and clever, but rather use this genre to create a context for exploration and experimentation.