Image source: mobygames.com
Analysis
I'm fascinated by the ripped R-Type sprites. They do not seem to have been ripped from the Amiga R-Type port, both because it came out the next year, but it's also not the same sprites, in fact they seem to match the original arcade machine sprites in pixel count, although the colors are obviously wrong. How is this possible? Almost noone would have had access to arcade machine ROMs in 1988. Are they manually redrawn based on a photo or a magazine ad?
The R-Type rips I have spotted so far are: the grey xenomorph, the orange walker, and the ball turrets
The stage 2 background is ripped from stage 5 of 'Armed Formation F', the stage 3 background from stage 6 of the same game, and again, it's from the arcade version of that game, the only port in existence was for the PC Engine and the graphics was much simplified.
The developer Kyle Hodgetts put out 5 Amiga games in 1988, including Cortex, which looks almost identical to Alpha-1, but with different ripped sprites from R-Type. One of the Cortex backgrounds is also ripped from Armed Formation F.
What's going on? How does this guy have access to 1988 arcade ROMs?