i had played this the other day thinking it was the 1988 version of Cobra Command. it really does look similiar. (i have fond memories of CC in a sit down cabinet with strange magnifying glass type glass screen, which was an interesting way to play a shmup type game.)

in any case, silk worm adds something with a litle bit of novelty in the ability to pick from two different crafts (jeep or heli) but i found myself not really liking it or finding it worthwhile. the bosses are cool looking but get recycled a second time around, and the backgrounds are alright. however, this isnt cobra command. and the sprites are very watered down looking from the original version. i found this game didt really captivate me in terms of gameplay or other aspects. it was however challenging. especially boss battles, as bulets fly fast and you must fly into their trajectory zone exposing yourself in order to attack their weak points. (sounds cool maybe but to me it just feels like a dirty quarter stealing design)

i have seen the game mentioned time to time. this one is IMO nothing special for nes. there are better shooters and (ported shooters) for the nes. the original itself is a copy of cobra command with the jeep gimmick.