| Amstrad CPC/PCW disk |  The Lurking Horror | 1987 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code |  The Lurking Horror Ver.203 | 1987 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Lurking Horror Ver.219 | 1987 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Lurking Horror Ver.221 | 1987 | Infocom, Inc. MA, USA 51051 |
| Apple II 5.25 disk | The Lurking Horror Model IH1-AP1 | 1987 | Infocom, Inc. MA, USA 51051 |
| Apple Macintosh disk | The Lurking Horror Model IH1-AP2 | 1987 | Infocom, Inc. MA, USA 51051 |
| Atari 400/800 disk | The Lurking Horror Model IH1-AT1 | 1987 | Infocom, Inc. MA, USA 51051 |
| Atari ST disk | The Lurking Horror Model IH1-AT2 | 1987 | Infocom, Inc. MA, USA 51051 |
| Commodore C64 disk | The Lurking Horror Model IH1-CO1 | 1987 | Infocom, Inc. MA, USA 51051 |
| Commodore Amiga 500 disk | The Lurking Horror Model IH1-CO4 | 1987 | Infocom, Inc. MA, USA 51051 |
| IBM PC 5.25in. disk | The Lurking Horror Model IH1-IB2 | 1987 | Infocom, Inc. MA, USA 51051 |
| Commodore Amiga 500 disk | The Witness | 1986 | Infocom, Inc. MA, USA 51051 |
| Amstrad CPC/PCW disk | The Witness | 1983 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Witness - An Interlogic Mystery Ver.13 | 1983 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Witness - An Interlogic Mystery Ver.18 | 1983 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Witness - An Interlogic Mystery Ver.20 | 1983 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Witness - An Interlogic Mystery Ver.21 | 1983 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | The Witness - An Interlogic Mystery Ver.22 | 1983 | Infocom, Inc. MA, USA 51051 |
| ACT Apricot PC Xi disk | The Witness Model IM2-AC1 | 198? | Infocom, Inc. MA, USA 51051 |
| Apple II 5.25 disk | The Witness Model IM2-AP1 | 1983 | Infocom, Inc. MA, USA 51051 |
| Apple Macintosh disk | The Witness Model IM2-AP2 | 1984 | Infocom, Inc. MA, USA 51051 |
| Atari 400/800 disk | The Witness Model IM2-AT1 | 1983 | Infocom, Inc. MA, USA 51051 |
| Commodore C64 disk | The Witness Model IM2-CO1 | 1983 | Infocom, Inc. MA, USA 51051 |
| CP/M 8in. disk | The Witness Model IM2-CP1 | 198? | Infocom, Inc. MA, USA 51051 |
| DEC PDP-11 disk | The Witness Model IM2-DE1 | 198? | Infocom, Inc. MA, USA 51051 |
| DEC Rainbow 100 disk | The Witness Model IM2-DE2 | 198? | Infocom, Inc. MA, USA 51051 |
| Epson QX-10 disk | The Witness Model IM2-EP1 | 198? | Infocom, Inc. MA, USA 51051 |
| IBM PC 5.25in. disk | The Witness Model IM2-IB2 | 1983 | Infocom, Inc. MA, USA 51051 |
| Kaypro disk | The Witness Model IM2-KA1 | 198? | Infocom, Inc. MA, USA 51051 |
| NEC PC-8000 disk | The Witness Model IM2-NE1 | 198? | Infocom, Inc. MA, USA 51051 |
| NEC Advanced PC disk | The Witness Model IM2-NE2 | 198? | Infocom, Inc. MA, USA 51051 |
| Osborne-1 disk | The Witness Model IM2-OS1 | 198? | Infocom, Inc. MA, USA 51051 |
| Texas Instruments Professional disk | The Witness Model IM2-TI1 | 198? | Infocom, Inc. MA, USA 51051 |
| Texas instrument TI-99/4A disk | The Witness Model IM2-TI2 | 198? | Infocom, Inc. MA, USA 51051 |
| TRS-80 disk | The Witness Model IM2-TR1 | 198? | Infocom, Inc. MA, USA 51051 |
| TRS-80 disk | The Witness Model IM2-TR3 | 198? | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | Trinity Ver.11 | 1986 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | Trinity Ver.12 | 1986 | Infocom, Inc. MA, USA 51051 |
| Infocom Z-Machine code | Trinity Ver.14 | 1986 | Infocom, Inc. MA, USA 51051 |
| Apple II 5.25 disk | Trinity Model IZ7-AP1 | 1986 | Infocom, Inc. MA, USA 51051 |
