# How determininstic is Metal Slug?

There are bonuses in the Metal Slug games that can change value wildly (e.g. from 30000 to 100), in an apparently random fashion.

I have the impression that at least some of them aren't completely casual: for example at the boss of mission 1 in Metal Slug 3 after following the submarine path, there are two POWs that give a bird nest which can be valued either 30000 or 1000: I have the impression that if you grab them closer to the boss and without shooting, you have a higher chance to get the better score.

I came across also this video, in which the player manages to max out all the random bonuses: I am aware that if the PRNG is queried/seeded continuously each frame it might be possible to cheat it by trying many times from the same save state until you get the best outcome, but I'm not sure whether that is what happened there.

So, my question is: is there any known logic in the value of the variable bonuses?

• If MAME replay playback is possible (it is) then it's almost certain that after starting a credit, everything is deterministic given an identical set of inputs. Many games will use techniques to "randomize" certain things by basing decisions on, say, the player's input or the value of the score counter on a certain frame, but that's still deterministic because the same series of inputs will produce the same output every time. – CloudyMusic Jun 9 '14 at 23:54
• Of course it is not strictly random, but having a PRNG in place makes it random for all purposes. My question is if the random draws themselves are intentionally biased to some outcome based on action of the player. – Lorenzo Pistone Jun 10 '14 at 10:39
• I can't prove this but I used to play MS a lot, and I noted that if I failed to rescue the archaeologist (and they got turned into a mummy) the next nearest bonus item was always garbage (like full of bats) instead of a golden bat or other high value item. So I suspect there were triggers that affected the outcome of some. – Amicable Jul 23 '14 at 14:45
• @Amicable, 2 or X? – Lorenzo Pistone Jul 23 '14 at 18:25
• MS2 it's the one I've played the most. – Amicable Jul 23 '14 at 18:27