The r-type series on the PC engine, and R-type 3 on the SNES are both fantastic. Also, blazing lazers on the PC engine (though I think it has a glitch that stops you getting past level 2?)...
Been playing Gradius V quite alot lately, and damn that game is hard. Makes you wonder... How someone can make a game so anoyingly hard, that still is overly addictive
Also Aeroblaster for PCE. It's called Airbuster for Mame, but I find the PCE version to be better :blink:
Oh yeah. Also Project X for the Amiga.... HARD! Never did get past level 2.