Catalogue of Arcade Emulation Software - the Absolute Reference

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Trog (rev LA5 03/29/91)

Trog (c) 02/1991 Midway.

One to four players take on the role of a cute dinosaur, selected from the four on offer : Rex (red), Bloop (blue), Spike (yellow) and Gwen (lavender). The game takes place in a prehistoric land called 'Og' and is made up of forty-nine different islands; the dinos must collect all of the dinosaur eggs that lay on the islands, while avoiding the unwanted attention of a tribe of one-eyed cavemen, called 'Trogs'. The dinos can punch the attacking Trogs; one punch will only stun a Trog but several punches will knock the enemy off the screen. There are four different Trogs who pursue the dinos :

* Brown Trogs who use only their fists.

* Red Trogs who use clubs and create fires or holes in the ground.

* Blue Trogs who pop up out of the ground and roll stone wheels.

* Green Trogs who bounce around trying to crush you with their springs.

On each island, after the dinos have gathered up all of their eggs, they must make their way to the base labeled 'Home'; from here they will move on to the next island.

Between each stage, there is an intermission where the players' Dinos will dance, with an on-screen caption proudly declaring 'Excellent!', 'Congratulations!', 'Nice Work!', 'Good Job!' or 'Dino-Mite!'. On occasion, an intermission screen appears that shows a Trog planning another attempt to eat a Dino.


Midway Y Unit hardware

Main CPU : TMS34010 (@ 6.25 Mhz)

Sound CPU : M6809 (@ 2 Mhz)

Sound Chips : YM2151 (@ 3.57958 Mhz), DAC (@ 3.57958 Mhz), HC55516 (@ 3.57958 Mhz)

Screen orientation : Horizontal

Video resolution : 396 x 256 pixels

Screen refresh : 53.20 Hz

Palette colors : 256

Players : 4

Control : 8-way joystick

Buttons : 1


* PROTOTYPE REV 4.00 : This particular code revision is also referred to in other resources as 'BattleTrog'. This prototype (known in Midway as Trog Proto 4) represents the original concept for the game Trog. The plans called for a strategy game where the player character, a dinosaur, had to be manipulated via placing bones to block his or her path, similar to many home computer games of the time. However, it soon became clear on field tests that players were confused and frustrated by this method of control in an arcade setting, where such strategic thinking was rarely required. Some surveys suggested that many players expected the game to be a simple "Pac-Man"-style affair. Many customers also were concerned/laughed openly at the action buttons labelled 'Bone', the term also being used in American slang for certain 'mature' acts and at least one cabinet panel was defaced to add an 'R' to the end of the word. As a consequence of this disasterous location test, the game was nearly axed entirely. Indeed, it probably would have been had it not been for the stop motion animation created for use as sprites in game - the story is that its high cost resulted in many of the senior employees at Midway demanding that Trog remain a going concern, with a new game mechanic built around the sprites. As it turned out, the game was turned into a "Ms. Pac-Man" clone, the small and large pills replaced with eggs and pineapples. It has been argued by some, including myself, that the use of trackballs instead of joysticks would salvage the original game mechanic, but closer inspection of the hardware through the MAME emulation suggests that 4-player trackball play, or indeed any trackball play could not be included without major complications, or indeed a whole new Midway hardware unit being devised.

* REV PA6-PAC : This prototype (known in Midway as Trog II Proto 6) represents the first major step towards the final Trog concept. The devitation from the standard naming system (the game would normally be listed as Trog PA6 only) represents the change in the project, the -PAc extension added to make it perfectly clear that this was a "Pac-Man" clone. With the original plans for a strategy game abandoned due to a poor location test, new thinking was required to salvage the project - it is rumoured that too much had been invested in the animation for the project to be canned at this stage. Money became very tight on the Trog II project (Trog I being the abandoned strategy game) and so a total rewrite of the concept was out of the question - they would have to make do with the existing code libraries for the project, with only minor alterations. Pushed for time and funding, the programmers decided to make the game into the Pac-Man clone many expected it to be, as this would require the least recoding, all that would be required would be to make the dinosaurs fully controllable, instead of the guided automatons they were originally. However, it was clear that the Trog AI would make them too good for even the best of players to overcome through clever moves, so a 'Punch' option was added which replaced the 'Bone' function and led to the only new animation added in the project, - a 3 frame jab which looked poor compared to that of the Trogs due to the time pressures on Haeger at the time of animation. But I digress... With this established, the programmers then altered the level order to provide a more suitable learning curve for the game, however this destroyed the main purpose of the 'Trog's Cave' intermissions screens and meant that the order of Trog's thoughts didn't fully match his actions. Also, although some of the 'thought balloon' animations (created on the fly through the game ROMS) were changed to remove the bone breaking scenes relating to proto 4, the cave drawings (done by professional 2-D animators) could not be altered due to time and money considerations. The original ending of the game was also scrapped, as it was believed to be an anticlimax, so another hastily animated island was added for an extra challenge, purported to be Trog's Cave (Note the use of the intermission style lettering coupled with superimposed text straight from the ROM, again new graphics were out of the question). However, most of the other features remained intact, with a Complex Egg Lay option being added in the release versions to allow owners to change the egg patterns back from the Pac-Man style to the original layouts (it is believed that there may be a version of the game which put the original mechanic back in too, but no evidence of this has been found).

A Trog unit appears in the 1991 movie 'Terminator 2 - Judgment Day'.

A Trog machine was shown at the 2003 classic arcade games show 'California Extreme' in San Jose, California.



* The bonus groove is still part of the released game's sound test, despite the fact it is now exclusively used for Trog's Cave and the ending - the prototype's bonus sequence was longer, as time and skill points were added, thus it needed music.

* The dinosaurs punch is poorly animated - this feature was added for the new game to allow fending off of the Trogs and as a result was just a few extra frames of animation made at the 11th hour by Jack E. Haeger.

* The last level uses the Intermission 'Trog's Cave' text, complete with graphical artifacts that were cut off on its normal background, due to the need to minimize adding graphics to the already overtime and over-budget project (the rest of the explanatory text is placed on screen using the same code that superimposes the victory messages).

* The Trog's Cave sequences no longer match up with the introduction of each new enemy - due to the restructure of the levels.

* Trog is seen trying to overcome bones in the recap drawings. In reality this scene was shot for the prototype, when the player's bones could be smashed or jumped on and not replaced due to the cost of redrawing the animation (it is worth pointing out that the main scenes have bone bashing elements removed).


While playing the game, try not to fall off the island. You must avoid or fight off any stone wheels that roll toward you and also avoid any tar pits that will occasionally appear. The Trogs are clumsy and dumb and will sometimes fall off the island, sink into the tar pits or blunder into their own traps. However, an island may have holes with warp grids that will advance your Dino two or three islands ahead if your Dino falls into it. These form when you take the shiny egg (in the lower-right corner, there will be one egg that will shine) last. In addition, all players will receive a cool 300,000 point bonus.

On some islands, there will be doors that will lead from one area to another and some will have springboards that will transport your Dino from one side of the island to another. The springboards will hurl the green Trogs to their deaths.

On each island, there are a number of special power-items to collect :

* 'Red roots' that give your Dino extra speed

* 'Yellow horseshoes' that will temporarily form a protective forcefield around your Dino

* 'Fiery chili peppers' that make your Dino to spit fireballs to burn the Trogs

* 'Ice jewels' that will momentarily freeze all the Trogs on the island

* 'Pineapples' that will temporarily turn your Dino into an unstoppable, Trog-eating tyrannosaurus rex.

Avoid the grey mushrooms as they will slow your Dino down.

Some islands have timed bonus stages that will give you a chance to earn bonus points. These stages include :

* Trog Feasts where your Dino will be a tyrannosaurus rex and will attempt to eat as many Trogs as possible before time runs out

* Trog Barbecues where your Dino will spit fireballs and try to burn as many Trogs as possible before time runs out

* Diamond Mines where your Dino will attempt to capture as many gems as possible (including diamonds, rubies and emeralds) before time runs out.


Artwork and playmation : Jack E. Haeger (JEH)

Game designers : Jack E. Haeger (JEH), George N. Petro (GNP)

Music and sounds : Chris Granner

Software : George N. Petro (GNP) & Kurt Mahan

Hardware : Mark Loffredo (M L), Glenn Shipp (GWS), Cary Mednick, Al Lasko (AL ), Raymond Gay, Sheridan Oursler

Cabinet designer : Ray Czajka (RAY)

Cabinet artworks : Linda Deal (LTD), Jack E. Haeger (JEH)

Publication : Karen Trybula

Marketing : Laura Rezek (LJR)


* Consoles :

Nintendo Famicom