Two ZX81 emulators which I've used are ZX81 (freeware) by Paul Robson and XTender (shareware) by Carlo Delhez; they both support .P files. XTender is somewhat more refined, but ZX81 has a built-in machine code debugger which is handy. However, I've only used them on old DOS PCs; I don't know how they'd perform on a modern PC; the processors might be too fast for them.
I can't recall where I got ZX81, there's no URL in the instructions, and the links which I tried from a Google search are all broken. However, XTender is still at Carlo Delhez's Xtender page. There are also some programs on the WoS Emulators page which are listed as providing ZX81 emulation and are probably more up-to-date.
Well a quick search on google tells me these dates...
Alien 1979
Aliens 1986
Alien 3 1992
Alien 4 1997
Predator 1987
Predator 2 1990
Alien vs Predator 2004
The Zx-81 was brought out in 1981 and the software lasted about 2 years
the was no games produced for the zx-81 in 1986 onwards
so you are wasting your time looking for any different Alien games for the ZX-81
Comments
I can't recall where I got ZX81, there's no URL in the instructions, and the links which I tried from a Google search are all broken. However, XTender is still at Carlo Delhez's Xtender page. There are also some programs on the WoS Emulators page which are listed as providing ZX81 emulation and are probably more up-to-date.
the one I use on my PC is "EIGHTY ONE"
this can be downloaded from the WOS site
This is the download link
ftp://ftp.worldofspectrum.org/pub/sinclair/emulators/pc/windows/EightyOne1.0.zip
this is EIGHTY ONE on my Quad core pc on Vista running Alien.p
ASH
Where have you find this rom ? could send me the "alien.p" rom ?
I could send you in exchange other roms about avp ot gryzor ?
http://www.rwapservices.co.uk/ZX80_ZX81/forums/
Why was not this rom on world of spectrum ?
Have you a collection of games about avp ?
1) It is: ftp://ftp.worldofspectrum.org/pub/sinclair/zx81/games/a/ (I think... I haven't compared them)
2) Because the ZX81 isn't a Spectrum.
When i says "alien vs predator". I mean games about alien, predator or alien vs predator.
Alien 1979
Aliens 1986
Alien 3 1992
Alien 4 1997
Predator 1987
Predator 2 1990
Alien vs Predator 2004
The Zx-81 was brought out in 1981 and the software lasted about 2 years
the was no games produced for the zx-81 in 1986 onwards
so you are wasting your time looking for any different Alien games for the ZX-81