Sega sure did create a lot of shmups for the arcade, and they are recognized for having two of the most famous shooting games ever: Space Harrier and After Burner. These shooters were not in the typical overhead Xevious camera or horizontal Gradius style, but they were set behind the back and brought the premise of 3D shooters into the limelight. They were not the first of their kind (Atari's fantastic Star Wars vector game beats Space Harrier by a few years), but their astounding scaling graphics earned them many a play in the public. While they became Sega's central shooter stars, they regardless made many a shmup in the more conventional planes, but they would usually do what they could to add their own twist to a normally formulaic genre. Regulus was an early attempt at a scrolling vertical shooter that put your extraterrestrial fighter on the ground and allowed you to fire in eight directions. Outside of these attributes, it was bland, slow, and not really all that noteworthy. Two years later, Sega would give the "landcraft shooter" another attempt with Heavy Metal, and although it also did not receive too much acclaim, it at least played and felt more enjoyable than its spiritual predecessor.
Heavy Metal commences in an incredibly awesome way: Your command ship boards the enemy docks, and your fighter rolls out, immediately firing off a missile to obliterate an enemy base. The camera pans alongside the missile's bird-eye view to make for a rather impressive intro. The camera then cuts back to your vehicle, which is some odd tank/hovercraft hybrid that fights against futuristic war machines. No one knows who or what the enemy is, but they stand for everything you don't, and they said you all look like dorks. Your vehicle has a fairly powerful gun that toasts nearly everything in one hit and is able to fire in eight directions. However, the real meat of the game is in your secondary weapon. That overhead missile you saw in the intro isn't just for show; you actually get to launch these with a semi-unlimited supply. They wouldn't be much good if you didn't know what you were hitting with them; this is why you have a handy radar on the left side of the screen which detects the position of enemy bases ahead. Whenever the radar picks up a ping, it indicates an enemy base which you can potentially nuke. You then hold down onto the missile button to send out its targeting cursor, and if you line it up with the position of a base, it becomes a direct hit. You're even able to adjust your missile's path midflight to properly align it horizontally. Your missiles do have a cool down gauge, and if you fire about five in a row, your radar turns red and you cannot fire another missile until it's back in the green.
Unfortunately, the missiles aren't so cool when YOU'RE the one being bombarded. Large enemy bases contain long-range firepower, so you pretty much need to use the radar and missiles to hit them before they can toast you. You can potentially keep dodging the missiles, but their splash radius makes them among the most aggravating hazards to evade, so make your best defense a good offense in this case. You can also blow their missiles out of midair with your missiles, though this can be tough to aim. If you fully wreck a large enemy base, you are awarded with a power-up sphere which constantly shifts between four colors. Grabbing it while it's red endows a super-shot, which makes your fire wider and more likely to hit evasive enemies. Blue gives you super missiles, which defy all spatial laws and wreck every building and opposing missile they pass over without requiring precise aiming. Yellow grants you a shield, which makes you completely impervious to attacks for about thirty seconds (making it the only impermanent power-up, while the others last for until you die or beat the level). Lastly, the green power-up is a much handy speed increase that will reduce the chances of you getting toasted by enemy fire, if only just.
There are four maps overall, with the first level starting on docks, moving over plains then getting into some weird highly advanced enemy base. The other stages include a desert, a ruined wasteland, and an acrtic landscape, yet they all inevitably end in bizarre futuristic bases too. On your treks throughout these foreign lands, you are beset by numerous enemy types, most of which fall into the "dart around annoyingly while taking fast potshots at you" subset. The challenge level gets to be quite tough early on with enemies moving faster than you and bullets clogging the screen. Every level also pits you against a boss which spits out enough bullets to qualify as a proto-Cave boss, and you need to hit it in its weak spot precisely with a missile.
Heavy Metal suffers from some of the same negatives as its predecessor Regulus, being that it gets more difficult than what feels fair and that the screen moves at a slow vertical pace. However, the diverse environments and boosted graphical power at least makes the game appear more visually engaging. The music's also upbeat and appropriately militant, and though no tune is particularly catchy, it is nice that each level gets its own music. Heavy Metal may not be the most astoundingly wild shmup of all time, and it would honestly be unremarkable if not just for its missile-cam gimmick. Missiles or not, it's still a fairly solid shmup that's worth a play or two, even though it has been quickly forgotten by Sega themselves.
Sega also released a quasi-port of this title for the SG-1000 under the name Super Tank. The levels are different, but mechnically it's almost exactly the same. The graphics have been downgraded, of course, but otherwise is plays fairly well.