0-3 is one of the most pivotal levels in the Prelude, simply because you obtain one of the most broken weapons you will cherish for the rest of your time playing ULTRAKILL: The shotgun. But patience is a virtue, so let's work our way through this level. The first room will greet you with a blinding light from the 4 light pillars that shoot up into the cieling. 2 STRAYS will spawn IMMEDIATELY, along with a few FILTH. You should have both variants of the revolver unlocked by now, but save the Sharpshooter for the next room. Tossing up a few coins can INTERRUPT the STRAY's casting of their bullet, causing them to explode. And as always, the jump and ground slam bait works like a charm on the FILTH.
The next few rooms may challenge your reaction timing a bit, especial on higher difficulties such as VIOLENT and BRUTAL. Upon entering the next hallway/room, you will be locked in with 4 STRAYS on every cardinal direction. Jumping up to the ledge where they stand and shooting a pre-emptively charged Sharpshooter bolt through the first stray will cause the bullet to bounce and kill hopefully many more. Stragglers can be taken care of with a simple headshot or even a PARRY if you are low on health. The next room introduces us to a new, stocky enemy: the SCHISM. SCHISMS are currenly being reworked but as of the current patch, they will charge up (longer than STRAYS) and shoot 5 bullets in a rough spread at the player. They are resistant to explosive damage and take more damage point-blank. They are easy to avoid but can cloud the sky with many a bullet if left alone for too long. Deal with them quickly! The next door will present players with a choice. (well, if you followed our guide that is.)
To the left after the SCHISM trio will be a staircase leading down to a bossfight with our favorite yellow friend, the SWORDSMACHINE. Just as described in 0-2, they are easily countered by good PARRY timing. However, this one is a PUSSY! he will teleport away and drop his shotgun and leave a rock at the door that you must blow up with the Core from the Core Eject shotgun. Now unfortunately, if you have already picked up the shotgun in 0-2, you do not get a second one. However, there is still value in doing this bossfight now rather than (spoiler alert) at the end of the level, because it shaves off half of the SWORDSMACHINE's health bar and strips him of his shotgun attack, leaving him limited to his limited arsenal of easy-to-parry sword moves. If you a like a challenge and already have the shotgun, you can also ignore this room and promptly scale the spiral staircase to the "insufficient Firepower" rock. Breaking through this rock with a core eject will bring you to the final gauntlet before the boss room of 0-3.
Before the boss room of 0-3, you must face a gauntlet of STRAYS, FILTH and SCHISMS to test your might with your new shotgun. Thankfully, performing a PROJECTILE BOOST by parrying and simultaneously shooting your shotgun's primary fire, essentially parrying your own bullets will make short work of every single one of these enemies. Be careful of the shredder and piston hazards in the second room, and press on. You will then come out onto a glass-floored staircase up to another staircase to the boss room, guarded by two stately STRAYS. Up the staircase and through the boss door is the final boss fight against the only remaining true SWORDSMACHINE. Same tips as always, except he has a few long-range attacks that can also be parried (although with some difficulty) for massive damage. But what if we told you: you can skip to this fight from the very beginning of the level?
If you're a good boy/girl/average ULTRAKILL player, you'll believe us. By performing a somewhat complex movement technique known as "slam storage", you can boost yourself from the opening room to the glass floor of the final boss room, which happens to be what those light pillars were pointing to this whole time! To perform a slam storage, jump onto the wall until you hear the grinding sound of your feet on the wall. Then, simultaneoulsy press your slide and jump button. you will jump off the wall, and float for a little bit. When you hit the floor, immediately press your jump key. You should blast off at insane speeds towards the glass floor above you. Just be sure to pre emptively shoot the glass, or else you will hit your head and slide defeatedly back to the gaping pit filled with STRAYS and FILTH that you just lifted off from. This eliminates pretty much all of the level's runtime and mechanics, and allows for some pretty high skill ceiling speedrunning tactics on repeat playthroughs. Get creative!