2600 Homebrew INV+ Released

[Albert]

Erik Mooney has completed his work on INV+, an original take of the arcade classic Space Invaders. This is the only version of Space Invaders for the 2600 to feature 11 invaders per row, matching the arcade game in this regard. INV+ is the successor to INV, with many improvements over the original game, which you can learn about in our Homebrew Discussion Forum. The binary for the game can be downloaded here, and you can buy a copy in cartridge form (complete with a new manual created by David Exton) from the AtariAge Store. Erik and Piero have also released the source code to INV+, which you can download here.

 

(Posting this here as I just added the game to our database, created the source code page, and the game added to the store a few days ago and I don't know how many of you read the Homebrew Discussion forum. )

 

..Al

[WildBillTX]

I really like the game but I kind of wish the invaders looked like aliens (like the mothership at the top of the screen) instead of blocks of green and yellow cheese. I hope that didnt offend you, just my opinion.

[Spirantho]

That's the price you pay for having the full complement of invaders, I'm afraid.... it's a matter of gameplay over graphics, so given we already have a Space Invaders with graphics, I think it's good to have a Space Invaders with gameplay as the presiding factor too.

[ErikM]

The invaders in INV+ are drawn with the console's playfield graphics, not the sprite graphics. If you're not familiar with the 2600's technical capabilities, just know that it's the same mechanism used to draw such things as the walls in Breakout and "mushrooms" in Centipede. The resolution available with playfield graphics is very low, of course, but that's just about the only way to get a full rack of 11 x 5 objects on the 2600.

 

The homebrew Space Instigators uses a very intricate hardware trick to get 9 invaders per line. That trick is actually extendable to 11, but has some problems; either the invader formation has to be very wide (almost the entire width of the screen), or you get display artifacts with the spacing between invaders becoming uneven.

 

So it's gameplay, not graphics, that drives INV+, of course. I took care to replicate as many other aspects of the arcade SI as possible. The 11x5 invader formation is a big part of the gameplay, of course, and there's several other details that match the arcade. Examples are the fact that invaders don't shoot in the last row before landing, and that the starting position of the invaders requires them to advance 11 times to reach Earth on the first level and one row closer in waves 2, 3, 4, and 7. Also, the saucer appearance, behavior, and scoring are dead-on for the arcade, an aspect where Instigators falls short.