Alright, after one year of important DDP playing (don't hesitate to say hi on twitch) and information gathering, I would like to post some updates:
- It is confirmed that the new 862 millions World Record is some kind of bug. The old World Record was 755 millions and the new run is essentially as "good" as the old one, with an extra ~110 millions obtained from the bug.
- forget about playing underpowered, or about carying the maximum bonus all along (this was already the case, by the way), there is one European player who managed to trigger a bug which generated an extra 15 millions out of nowhere. The player is Bananamatic and has, by the way, the community record at DDP (best score outside asia), which is currently 608 Millions.
- The goal of this post is to share all the things I know because it would be great to have more people investigating for this bug. So here is what I know :
1) Bananamatic triggered the bug in stage 1-6 (i.e. first loop, stage 6) while he was training, using mame, with savestates. Unfortunately, he did not record his training; nor does he have an .inp file to share because you can't record an .inp file from a loadstate. It is thus not possible to replay what he did. I can only detail what he told me.
2) The route used by Bananamatic in 1-6 is essentially the chaining route of this video:
https://www.youtube.com/watch?v=Ovf6xpH4dRE&t=1028
Bananamatic remembers he did a full chain (from the beggining, till the end of the stage) of approximately 809 hits (which is quite standard, and in fact quite low for a full chain). He did NOT use any bomb. The savestate he uses starts at 1-6 with a score of 127millions. After the chain is over (so before the boss of stage 1-6), he noticed he had a score of 208 millions, which is ~15 millions more than what he's supposed to have. We thus know that the bug is not triggered by bombing, and is not a bug on the boss.
3) From another source, which knows what the bug is (but cannot share it for reasons I won't discuss here) the bug is hard to find; but is not something completely gamebreaking which ruins the scoring of the game for people interested in superplays.
Given these informations, I'm now sharing my thoughts:
- stage 1-6 has some unique enemies which never appear in other stages, namely those small turrets which fire small blue lasers and which respawn.
- I now believe the bug lies in calculation of the points you get from your chaining. Namely the "GP", sometimes called "base points" of some enemies. In short, each enemy is supposed to give some "base point". When you do a chain, whenever you kill an enemy, you obtain the base point of the enemy you killed plus the base points of all the enemy killed before in the same chain.
So if b_n is the base point of the enemy for the n^th hit, this hit gives you
b_1 + b_2 + ... + b_n points.
Now if for some reason, you manage to glitch the base point of an enemy; the extra points you get will clearly snowball.
For example, in a chain of 800 hit, if b_1 is normally equal to 100, but you manage to glitch b_1 to be equal to 10'000, then you will get an extra 800 * 9'900 points, which is a bit less than 8 Millions.
If you manage to glitch more than one enemy, you would get more...
I am not aware of any technique to glitch the base points of an enemy, but here TASing might prove very useful.
- Given the relatively low hit count (~800 hit) that Bananamatic did, we have confirmation that the glitch does not come from some crazy, glitched, hit count.
- To come back to the base points of each enemy, I would draw your attention on whether
(a) the base point can be manipulated by changing the way you kill the enemy (with the shot, the laser, the aura, point blanking)
(b) the base point can be manipulated by killing more than one enemy at a time. We already know that when you do a chain, the hit count can be slighty increased by lasering two enemies at a time. So maybe the game does not handle well multiple simultaneous kills.
So there you go. Sorry for the tl;dr. I strongly believe that a careful analysis of this stage 1-6 using TASing tools would help to solve the mystery. Of course, I plan to work on it. Please don't hesitate to do the same and share your thoughts.