Mortal Kombat 1 PC DOS Version Comparison

Previous: Configuration, Graphics, Audio


In the rest of this section the following notation will be used: F, D, B, U – Forward, Down, Back, Up; HP – High Punch, LP – Low Punch, HK – High Kick, LK – Low Kick, BL – Block.

All DOS version of MK1 support the same basic configuration options: keyboard, 2-button joystick, 4-button joystick and joystick&keys. In the last mode, a joystick is used for movement only, and keyboard keys for the buttons. If a 4-button joystick is used by one player, the other player must use keyboard or joystick&keys. However, two 2-button joysticks can be used at the same time.

Since MK1 needs 5 buttons, in 4-button joystick mode the buttons are used for LP, BL, LK and HK, and HP is F+LP. However, special moves that require HP are executed by just pressing LP, without requiring F.

In 2-button mode, the changes are more significant. The buttons are used for HP and HK. LP and LK are achieved by combining the buttons with F, and BL is B+HP. Many of the special moves that would have no natural motion for a 2-button joystick have been altered. For example, Kano’s knife throw is not Hold BL (B-F), but simply B-B-F. Cage’s split punch and Sonya’s leg grab are just D-D-Punch instead of pressing multiple buttons at the same time.

Joystick support exists in all versions, but something in the code was changed in the CD version, making it more finicky, at least in DOSBox. With cycles=max setting, the joystick drifts as if one of the directions is stuck. Configuring it for two joysticks would get the game and the emulator to lock up. Using a fixed value for cycles, even a high one, appears to work around the first issue, but not the second. The floppy versions do not exhibit any of these problems.

When it comes to keyboard control, Alpha/Beta do not have an option to configure the individual keys. They both contain two text files – GRAVIS.TXT and KEYS.TXT – in the game directory which list the controls for each action, respectively for a Gravis or any similar 4-button stick/pad, and for the keyboard.

Starting from the Release Candidate, which has SETUP.EXE, it is possible to define every direction and action key for each of the two players. The defaults are the same as specified in KEYS.TXT. It is not possible to change the button assignment for joysticks, though. It is also impossible to change the user interface keys. These vary a bit between versions, as summarized in Table 2. Player 1 / Player 2 start buttons are F1/F2 in all versions.

Version Pause / Unpause Quit Match (‘Game Over’) Enter Setup Exit Game
Alpha / Beta P n/a n/a ESC
Release Candidate Alt+P ESC n/a Alt+Q
Floppy Versions Alt+P ESC F10 (during demo) Alt+Q
CD Version Alt+P F10 (during match) F10 (during demo) Alt+Q

Table 2. User interface keys in different versions of MK1.

Special Moves

The Arcade version had a couple of moves that require pressing several keys simultaneously. These are Sonya’s Leg Grab (D+BL+LP+LK) And Sub-Zero’s Slide (B+BL+LP+LK). This is not a problem with a stick/pad, but many keyboards, then and now, have a problem registering more than 3 (in some cases even more than 2) simultaneous keypresses. The programmers of the PC port apparently understood it at some point, therefore, when a keyboard is used, these moves were simplified in the official versions to require only 3 keys: BL+LP+LK. When a 4-button joystick is used, the moves still require 4 buttons.

In the CD version only, Sonya’s move was further simplified to only LP+LK, but Sub-Zero’s move still requires BL to be pressed. This is probably an unintentional omission, seeing as in the DOS version of MK2, which was released before the CD version of MK1, Sub-Zero’s and Reptile’s Slide was also simplified to LP+LK.

Additionally, Sonya’s Ping Rings move, which in the arcade had the weird sequence LP-B-LP, was also somewhat simplified to B-B-LP, although this is not due to any keyboard limitation. This change is for joystick as well as keyboard.

Of all the versions, only the Virgin Beta remains true to all the Arcade button sequences for the special moves (for some reason, the Alpha simplified Sonya’s move but not Sub-Zero’s). This means that in the Beta, these would be quite hard to execute on a typical keyboard. To add insult to injury, other moves are also hard to pull off in the Beta, probably due to sensitive timing issues. For example, Cage’s Split Punch (LP+BL) almost never works, and even simple moves like D-F-LP for Sub-Zero / Raiden sometimes do not register. Strange as it is, it may make the awkward 2-button joystick an easier controller in some ways than a 4-button joystick / keyboard, for this version.

Table 3 summarizes the different key combinations for the special moves that varied from version to version.

Version Sub-Zero’s Slide Sonya’s Leg Grab Sonya’s Projectile
Arcade / Virgin Beta B + BL + LP + LK D + BL + LP + LK LP – B – LP
Floppy Versions BL + LP + LK BL + LP + LK B – B – LP
CD Version BL + LP + LK LP + LK B – B – LP

Table 3. Evolution of special move combinations in keyboard mode


The differences in gameplay between the different versions are more numerous than is obvious at first, but some are quite subtle.

The most obvious and meaningful change is the speed at which the game plays. All the early versions, up to and including the final Ultratech release, play quite a bit slower than the final Arcade releases, more like the early Arcade drops which were also a bit sluggish. The final Virgin release and the CD version boosted the game speed to be comparable to the final Arcade version (T-Unit 5.0). This is mostly a good thing, and partially closes the speed gap between MK1 and MK2/MK3.

Not just the movement speed was affected, but other timers as well: there is less time on the character select screen, and the round clock ticks down faster as well. Early versions have 19 seconds on the select screen and 65 seconds per round (except the Alpha which has 60 seconds for some reason). The final Virgin floppy has 16 seconds on the select screen and 60 seconds per round. These times are in line with the Arcade. Interestingly, the CD version further sped up the clock, so a round is only 55 seconds long in this version.

There are a few of changes that affect combat (in fact, there are probably many small ones, but the deep and specific research required to find them all is beyond the scope of this comparison). The most obvious one is that in Alpha/Beta you can block a sweep with a standing block; in later releases (as in the Arcade) a sweep will defeat a standing block. Consider the animations in Figure 4.

mk_sweep_beta  mk_sweep_final

Figure 4Standing block vs. foot sweep. Left: beta versions. Right: final versions

The Release Candidate changed the collision boxes to be larger than in the preceding versions. This change stayed in the first Ultratech release, but was reverted in the final releases. This makes the collision boxes in these two versions significantly larger than the sprites, so moves reach and connect when intuitively you think they should not. It is most obvious with jump kicks: in these versions many characters can connect a jump kick from full screen (Figure 5), and it is also possible to land a jump kick from very close range, so that you connect with your butt to the back side of the opponent, after you already switched sides with him (Figure 6). It looked and felt really weird the first time it happened to me. Other moves are also affected – some characters can hit you with a roundhouse from 3 steps away, or with an uppercut 2 steps away. Normally, a jump kick would defeat a projectile fired as the kick connects, but in these versions, more often than not, either the projectile defeats the kick, or both hit and both players fall down. All in all, it affects the gameplay in a variety of unexpected ways, which is probably why the developers reverted the change and went back to normal collision boxes in the final drops.

fullscreen_jumpkick_hit  fullscreen_jumpkick_miss

Figure 5. Full screen jump kick. Left: Ultratech V1, Right: Ultratech V2

close_jumpkick_hit  close_jumpkick_miss

Figure 6. Close range jump kick. Left: Ultratech V1, Right: Ultratech V2

Other gameplay changes do not affect the combat directly. Free Play is a major one. Alpha/Beta had it always on. Since the RC, it is off by default: you start with 5 credits which means you can only lose 4 times in 1-player mode before it’s game over. In versions with the built-in F10 setup, DIP switch #5 can be used to toggle Free Play. This makes RC the only version where it is impossible to turn Free Play on.

The functionality of DIP switch #6 changed at some point. In early versions it did nothing. In the final Virgin and CD releases it can be used to make the shadows over the moon at The Pit stage present in every battle (instead of every 3rd or 4th one by default). This makes it possible to reach Reptile after every Pit fight in 1-player mode, and was probably done to simplify testing. As a result, it is theoretically possible to reach him twice during a single playthrough, which would normally be impossible (unless you lose a lot), since there would never be shadows on two consecutive Pit fights. In all versions, however, if you beat the game, and start a new one, the next fight at The Pit will have shadows.

Another Reptile-related change has to do with him dropping down and giving hints for finding him. In the Alpha he drops down before every round in every fight, which is very annoying. In the Beta they took this out completely – Reptile never drops down to give hints in this one (although he is still in the game, and you can fight him). In all later versions he drops down randomly, perhaps once in a few tens of rounds.

In Alpha/Beta, switching from 2-player mode to 1-player mode resets the winning streak (if the streak was long enough to enter the high score table, it will be registered before continuing). This behavior is consistent with the Arcade. In later versions it is not reset – all wins in 1-player and 2-player mode count towards the streak, which is only registered and reset after the player loses, or beats Shang Tsung and wins the game.

Next: Music, Miscellaneous, Summary and Conclusion


4 thoughts on “Mortal Kombat 1 PC DOS Version Comparison”

  1. If you look closely at the Scorpion and the skeleton, it is noticeable that the developers tried to remove the sprite border.

    1. Thank you for the translation, and for referencing this blog. If you don’t mind, please add a reference in the first part as well, since they are separate forum threads.

      You did a terrific job; I didn’t spot any mistakes and your style is good. 🙂 Great catch about the Arcade resolution. For some reason I assumed it was higher than it is. I will fix it in the write-up.

  2. It seems to me based on the file date that the first US release version was hurried out to get it in stores before Christmas (which they just barely did) only for a few bugs to remain. In Europe, where Virgin handled distribution, they didn’t rush so the bugs were addressed before release, as they were for the second shipment of the US distribution. At least they sent out a patch disk for those who bought the first shipment in the US.

    And although I agree that it would have been cool for the GOG release to allow for the Sound Blaster/Ad-Lib or MIDI versions to be played (Or even the PC speaker just for kicks), I’m just glad it’s readily available, since it’s still the best home port of the original.

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