A test run for some new strategies for in an eventual 100% TAS of Blaster Master.

Afterboss death glitchDying at the very exact frame necessary allows you to lose a life and yet keep the 'boss is dead' flag up. Any earlier and Jason died for nothing. Any later, and the fadetoblackandback screen transition out of the boss mode occurs, wasting more time. There's also a period of a small handful of frames where the game refuses to go on to the next life, leaving Jason's corpse onscreen, lifeless, forever.

Boss room refusing glitchBy pressing back towards the door on exactly the right frame, Jason will leave the room just as the boss is appearing, causing the boss fight to continue in the wrong room, with very weird results. You can move between rooms at this point and the boss will just keep following you. If you leave the underground, everything goes back to normal, except the boss fight music stays playing! For the most part, however, this is useless to a TAS.

The point of these two glitches as TAS strategy as that using the first glitch mentioned (along with the second if necessary, Area 1's boss for example, since he shoots no projectiles) reduces the number of times the TASer will have to die after beating the boss in Area 3 to cause the continue screen deathwarp back to the start of the Area, saving loads of time. I'd say it also adds to the entertainment value of the run, flipping out the screen like that.

Since I'm feeling longwinded, an explanation of the visual glitching: Blaster Master's bosses are not sprites. The game was programmed in a clever, sneaky way to make it all look great and flow well. The bosses are actually entirely on the background layerthis is why the screen fades to black for the bosses; the floor tiles are removed and replaced with the boss! Sure, parts of the bosses are sprites (like say Area 5's lobster boss's eyes), explaining why they disappear when the game pauses, but for the most part the boss is animated by changing the background tiles and scrolling the background. You know how clouds move in the background sky in some games slightly differently from the player to provide the illusion of depth? That's what they used to move the bosses around here.
That's why fighting the boss outside of the boss room screws things up so much. The background layer (the boss's graphics) is replaced with the background layer of the new room, namely the floor pattern wherever it appears. It's also why everything moves around so strangely, it's the scrolling technique to make the boss move around.
I haven't actually tested this with most of the bosses, I'm sure it looks slightly different for every one. I also wonder about the final two bosses, since I assume that they're both done with sprites and the background doesn't scroll. Another time perhaps.