Mouse Trap discovery?

[DEBRO]

Hi there,

 

Here is an interesting discovery I hadn't seen reported.

 

While disassembling Mouse Trap I see there are 4 cats instead of 3. The 4th cat (i.e. top most Cat) is disabled on purpose. I wonder if they play tested the game and the testers found it more difficult with 4 cats.

 

You can enable the fourth cat by filling $FF82 - $FF8C with $EA (i.e. NOP). The fourth cat will then be enabled at the start of the next game or rack.

[Bomberman94]

1 hour ago, DEBRO said:

Hi there,

 

Here is an interesting discovery I hadn't seen reported.

 

While disassembling Mouse Trap I see there are 4 cats instead of 3. The 4th cat (i.e. top most Cat) is disabled on purpose. I wonder if they play tested the game and the testers found it more difficult with 4 cats.

 

You can enable the fourth cat by filling $FF82 - $FF8C with $EA (i.e. NOP). The fourth cat will then be enabled at the start of the next game or rack.

Maybe this is a start of a new hack? ?

[Thomas Jentzsch]

Cool finding.  

 

Reminds me at hidden the reserve ships graphics in Asteroids.

Edited March 9, 2021 by Thomas Jentzsch

[Tempest]

Interesting.  Does it cause a lot of flicker or anything?  I'm not sure if difficulty explains it because the arcade game has up to six cats IIRC.

[DEBRO]

Hi Matt,

On 3/9/2021 at 2:36 PM, Tempest said:

Interesting.  Does it cause a lot of flicker or anything?  I'm not sure if difficulty explains it because the arcade game has up to six cats IIRC.

Only the maze "flickers" to show the Trapdoors. There is no character flicker in Mouse Trap. They keep the Cats vertically separated to avoid flicker.

[+save2600]

Very cool discovery! Wouldn't mind trying a more difficult version of this beloved classic. Would you mind posting a hacked .bin so we may try it using Harmony and a real Atari?

[+SpiceWare]

On 3/9/2021 at 7:50 AM, DEBRO said:

You can enable the fourth cat by filling $FF82 - $FF8C with $EA (i.e. NOP).

 

Looks like that should be thru $FF8D

 

4 hours ago, save2600 said:

Would you mind posting a hacked .bin so we may try it using Harmony and a real Atari?

 

Mouse Trap 4 cat hack.a26

[+save2600]

Finally got around to trying this. Always thought 3 cats a little too easy, and seemed I could play forever when in the zone, but 4 is pretty tough! Or just right... I can't decide. ha   Probably a good decision to go with 3 at the time of release. Just would have been nice to have had 4 as an advanced option BITD.

 

Thanks again DEBRO and Spice, having a blast!  

[Superkitten]

That's really interesting.  I never noticed that the cats' AI is based on the maze shape and location of other cats, as they will not move into the vertical row where there is already a cat.  With 4 cats on the difficulty setting B (dumb cats), they spend a lot more time just moving back and forth, not really going anywhere.  They don't chase the player, they just bop around according to maze shape and the locations of the other cats. Edit: Even on the Difficulty setting B (Smart Cats), they can get boxed in vertically by the other cats.

Edited June 1, 2021 by Superkitten

[Atariperson23]

Very interesting. I wish we could see more discoveries like this. I always thought the original game was a tad too easy.