https://docs.google.com/spreadsheets/d/1PX0gEhoN1S3vYtR_zdm2FYpKn4PQhWN-Xc5bivqOUnw/edit#gid=0 When looking at this chart remember. Each gun level has it's own drop chart. The drop chart resets to the beginning and goes to the next, or lower level with gun up and gun down. If you have the whip equipped and get a whip up or down the table also resets, but stays at the same drop tier.

Killing a monster does not guarantee a drop will occur, but the item that does drop will be the next one in the list.

Here are the most common methods of farming. (R = Rank of gun) Something like "2 drops to R2" means to get the gun upgrade to climb to next

11 key Any% (11 keys used in any% record atm 12/27/21) (+1 if using potion, -1 if doing 2 key whip, +? if doing more than 3 key whip) 2 first hospital, 3 at whip house, 2 fourth hospital, 2 last hospital, 1 noose, 1 final

R3 method It's 2 drops to R2, 6 drops to R3, and then 10 drops per key till end (except last is only 6) so 1 key is naturally obtained getting to r3 (8drop) and then another 10 keys need to be farmed after at R3. so 8 + (10x9) + 6 for 11 keys 104 (This is the simplest method and easiest to fix if an accidental gun up is grabbed without the gun down, just adds 2 extra drops to gun down)

R4 method (never getting whip, almost a trash strategy) 2 drops to R2, 6 drops to R3, 8 drops to R4 (2 natural key drops on the way), and then 16 drops to get the 2 keys on the R4 tier with only 12 needed for final key (first key drop of R4). So 16 drops to get first 2 naturally 16x4 for next 8 and then 12 to finish. So 16 + 16x4 + 12 92 (This is a little more viable on pal due to shooting through walls but getting the third key if skipping enemies might be tricky before whip unless you farm in sewers before first boss, or after first boss)

R5 method (Semi complicated requires whip.) So same thing 16 drops to R4 (2 keys), and then you get 12 drops into R4 but the key and gun upgrade must be on the screen at the same time so you can pick up both (1key) so 28 drops to hit R5. At R5 you then farm 12 drops into it (having whip and key on screen at same time to grab both) and you get 2 keys per cycle. So 3 keys naturally for first 28 drops. and then the other 8 keys in R5. 28 + (12x4) 76 (Side benefit is that for this strat you only need 3 keys before the whip house in the first place. But farming after you get this is rough due to the slime spawns in the sewer where I farmed due to narrowness of passage making it easy to hit the wall, be blocked by a red, etc. So for NA at least, it is more difficult but possibly more rewarding.)

6 Key Nooseless (+1 if using potion good for new players) 2 First Hospital, 1 Whip house, 2 Last Hospital, 1 Final Math same basic, need 2 first hospital, 1 at whip, 2 last hospital, 1 final

R3 First key natural then grind 8+(10x4)+6 = 54 drops

R5 First 3 natural, then small grind 28+12+5= 45 drops

9 Key Glitchless (+1 before first dungeon if using potion, +1 after 4th dungeon if getting noose, both recommended for new players) 1 TNT, 1 Invis potion, 1 for first hospital, 1 for whip, 1 for second hospital, 1 Rockets, 2 for next two hospitals, 1 Noose, 1 for fifth and final

R3 8+(10x8) = 96 drops

R5 28+(12x3)+4 =80 drops

(Yell at me if my numbers are off lol)