SURVIVAL RUN

Gordon Taylor made a TAS run of this game, up to and including the 8th maze.  The approximate time (in minutes:seconds) it takes to travel through each tunnel is as follows:

Tunnel 1 - 7:30
Tunnel 2 - 6:00
Tunnel 3 - 5:55
Tunnel 4 - 5:00
Tunnel 5 - 4:45
Tunnel 6 - 4:00
Tunnel 7 - 3:30 (Limit of real-time play?)
Tunnel 8 - 2:50
Tunnel 9 - 2:15
Tunnels 10 and up - 4:45 each

Although the game manual mentions five different skill levels, the game continues to get faster and harder if you make it past the fifth skill level/tunnel, eventually to the point of partly breaking.

Tunnel 7 is likely not possible to beat in real-time, even by experts, due to how fast both enemies and force fields are coming at the player.  It can be beaten with tool-assistance, however.

Tunnels 8 and 9 are playable and beatable with tool-assistance, however it is impossible in those tunnels to hit a "crosswise" force field box (i.e. one that spawns on the right after you make a left turn and vice versa) - you just don't have enough time to move the cursor across the screen and fire the necessary shot.

Tunnels 10 and up are bizarre and likely bugged - there are very long turning scenes and very short amounts of time (only a second or two) in the tunnels themselves!  Also, enemies and force field boxes (including the end boss) will barely move at all.  At most, with tool-assistance, you'd only be able to hit a few enemies before being forced to move on.  Further glitches may exist if you keep going with tool-assistance, but there's little real reason to considering it's likely not possible to reach these tunnels in real-time runs.

Because the lowest amount of points that can be scored at one time is 80 points, a legitimate score will always end in 20, 40, 60, 80 or 00.

The score rolls at 1,000,000 points - so far, this only has been done (and may only be possible) in a tool-assisted run.  The rollover causes the game's timing to be reduced by one frame from what it would've been otherwise, but no other effects are seen.

The scoring formula in the manual can be expressed as follows, letting T equal the number of the tunnel the player is currently in:

Alien guard = (T+2) x 100 points each
Force field = (T+5) x 100 points each
Alien command ship = (T+5) x 1000 points

Besides the scoring formula, another formula programmed in the game (but not mentioned in the manual) determines how enemies are spawned in each tunnel section; however this formula would only be visible in a tool-assisted run, as a real-time player simply cannot shoot enemies fast enough to make the formula obvious (except possibly in the first tunnel) and the game would seem to be endlessly spawning enemies upon reaching the second or third tunnel. Again, we let T equal the number of the tunnel the player is currently in:

Empty initial section (except for T=1, see next entry)

Five cycles of four sections, with enemies spawning as follows: force field and (T+1) alien guards, (T+3) alien guards, force field and (T+3) alien guards, (T+5) alien guards. Each section ends with a turning option that the player must choose correctly to move on - choosing wrong or hitting the center pillar = game over!

Sixth cycle of four sections ends tunnel, this cycle is the same as previous five except alien command ship replaces (T+5) alien guards.  Next tunnel starts after this.  {Gordon Taylor}

The initial section of the first tunnel seems to have enemies that indeed spawn endlessly, and after the first few will always spawn in the same place.  This means a tool-assisted run can pick up over 25K points (!) in that first section, and even a non-TAS player can get at least a few thousand there.  This behavior is different from what happens in the initial sections of subsequent tunnels, but whether this was a deliberate programming choice or the result of a bug is not clear.  {Gordon Taylor}

BUG: High-speed bug #1 - The game usually does a pretty good job of keeping everything animated smoothly despite the heavy graphical effects of traveling through the tunnels. However, at the highest game speeds (tunnel 5 and higher) subtle graphical bugs begin appearing, doubtless because the game can't keep up with everything graphics-wise at the higher speeds.  One such bug is the black HMOVE line between the tunnel map and main view will "jump" when the player is firing - it seems to actually split in two when a shot is traveling down the corridor, and then recombine after the shot either hits an enemy or the far end of the tunnel section.  {Gordon Taylor}

BUG: High-speed bug #2 - Another bug that appears at high game speeds affects how the score is updated after hitting an enemy.  If a digit is changed twice during the same scoring event (for example, 39+11=50 or 49+12=61) the score will display an incorrect "intermediate" value for one frame before being fixed, either with a blank space (picture #1) or garbage graphics (picture #2) in place of one of the digits - what exactly appears depends on how far the "overshoot" is from 9.  This occurs rarely at first starting with tunnel 6, but becomes fairly common in tunnel 9 onwards.  {Gordon Taylor}

 

 

 


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