I wanted to bring this up in a new topic since the Dandanator Mini got its own one. The Sinclair Interface 2 is an official cartridge ROM interface for the ZX Spectrum with 10 commercial titles as quoted below (from the ZXS wishlist). I figured an official peripheral would get better support compared to a homebrew one.
TakuikaNinja wrote:
One wish I have is for ZXHawk to implement support for Sinclair Interface 2 (IF2) ROM cartridges. There were only 10 commercial releases in this format:
Jetpac
PSSST
Cookie
Tranz Am
Chess
Backgammon
Hungry Horace
Horace and the Spiders
Planetoids
Space Raiders
Prototype cartridges, third party conversions of various tape games, and unofficial cartridge hardware (>16KB ROMs) exist, but support (and movie publications) for these would be a low priority. There is a homebrew game called Mag the Magician which has a cartridge release. Various utilities like system test ROMs, ZX80/81 emulators (128K units only), and a bugfixed 48K system ROM also exist.
The interface works by disabling the system ROM at $0000~$3FFF (ties /ROMCS to 5V) and mapping the cartridge ROM in its place. Details can be found at http://www.fruitcake.plus.com/Sinclair/Interface2/Interface/Interface2_Circuitry.htm. See Fuse for an emulator which implements IF2 ROM support.
Note that the interface (including its joystick ports) does not work on +2A/+3 units due to incompatible pinouts. That behaviour should be emulated.
Advantages in terms of TASing:
No tape loading is required, so movie times will better reflect actual gameplay
Game selection has good quality (PSION, Ultimate)
Disadvantages in terms of TASing:
Limited game selection
All commercial releases had tape versions (and the load times are already fairly short due to them targeting 16K units)
Limited unit selection due to +2A/+3 incompatibility
Only permitted joystick type is Sinclair, otherwise keyboard controls will need to be used
If IF2 ROM cartridge support is not being considered, then one can just treat this post as a wishlist for the games mentioned here.
Don't mind me, I was born on Friday the 13th.
(I'm not TASing that NES game, okay?)