
该游戏是台湾和众科技(RealTec)开发的SuperGame系列之一,该公司的FC游戏大都是仿Sega MD 的作品。
多年前我有幸供职于该公司的深圳开发部,就是柏青哥实业有限公司(和众科技的合伙人),并参与了该游戏的程序开发。游戏的全部背景画面和卡通都是通过该公司自己开发的一个硬件仿真器从同名的MD游戏中抓出,并做了降色等简化处理。为了防止被被别人盗版,该公司自己还开了颗改版的MMC3(Mapper 4)用来加密,并且都以合卡的形式生产发布,合卡中的第一个游戏是自己开发的,后面的一般都是“公共版本的游戏”。程序员做开发时还是用标准的MMC3(Mapper 4),所以我这还保留了该游戏的一个MMC3的前期半成品版本,等游戏做到差不多了时,老板就拿到台湾去做后期加密工作,所以公司后期的作品几乎都没有被盗版,而先前开发的“狮子王”由于采用标准的MMC3发布,所以两个月后就被别盗版了。
由于现在的模拟器技术和Dump技术的空前发展,Super Game的合卡系列几乎都被俄罗斯cah4e3小组一一Dump,并被分配了mapper 217。地球虫2(Earth Worm Jim 2)就被收录在合卡Golden Card 6-in-1 (SPC009) (Super Game) [!]中,Cah4e3对它的说明如下:
Origianl version of Earth Worm Jim 2 for Famicom. Unlike EWJ2 by Shin-Shin Electronics, this version much accurately ported from SMD but have less comfortable controls and game mechanics. Game has not any passwords, but have almost full-fledged "Puppets Catch" level.
As I see, it is the last version known series EWJs for Famicom, but it is talked about one more EWJ game with number 4. Maybe this game not exists at all, maybe it is some hack or something.
Some time earlier i've dumped similar game. Current version comes as parential version of MK360extra and have two times less CHR and PRG roms. Differences between both games is in Player Select screen and recently dumped one have Versus screen before fight, but most advanced one have not. In general it is similar games.
This ROM works on 217 mapper, while old one works on 215 mapper which is the almost the same as 217, but have another permutation block for mixing up registers. Both games needed much accurately IRQ emulation, because IRQ signal occurs some lately than needs and game background draws lower at screen.
不久前细胞研究所(任地狱)网站的站长(FC山寨游戏收集者)--madcell,给我发了个他从该合卡中单独吸出的Earth Worm Jim 2 游戏ROM,可惜合卡的菜单程序是混合在该ROM中没能跳过,就想叫我帮助将合卡的菜单从这个游戏中去掉。我分析了该ROM的代码,发现菜单的按键程序如下:
AF9E: A5,0E LDA $0E ;得到手柄值
AFA0: 29,D0 AND #$D0 ;判断是否为A,B,START按键
AFA2: F0,F7 BEQ $AF9B
我就简单地改掉判断,让程序直接跳过菜单处理
AFA2: EA NOP
AFA3: EA NOP
至于菜单的显示,我直接用YY-CHR工具将字模给去掉了(有点不好意思啊!)
由于支持Mapper 217的模拟器我目前发现只有Cah4e3改版的FCEU-MM和另一个Nestopia模拟器可以模拟,所以大家要用这两个模拟器来玩它,而我的另一个半成品版(工程版):Earth Worm Jim 2(test versin).nes是采用mapper 4的,用普通的模拟器就可以了。我将来也想抽点时间将mapper 217恢复为mapper 4,这样一来就方便了。
可惜的是由于当时的保密协定,地球虫的源代码我已经从硬盘中删掉了,我目前只有SuperGame的"风中奇缘(Pocahontas)"和"马桶先生(Boogerman)"的source code,请看我前期发表的文章:我们团队做过的FC原创游戏(带源代码),在我的maxzhou88 web disk中有这两个Game的source code.
ROM下载地址:maxzhou88.ys168.com/NES/FC-Earth Worm Jim 2.rar 372KB