Ghost Pilots1991

Sky Shark (released in Japan as "Hi Sho Zame", and in Europe as "Flying Shark")is a military-themed vertically scrolling shoot 'em up game in which players take control of the titular biplane through five increasingly difficult levels in order to defeat an assortment of military enemy forces like tanks, battleships, airplanes and artillery as the main objective. The title initially appears to be very standard, as players control their plane over a constantly scrolling background and the scenery never stops moving until a runway is reached. Players have only two weapons at their disposal: the standard shot that travels a max distance of the screen's height and three bombs. The bombs are powerful weapons capable of obliterating any enemy caught within its blast radius. Various items are scattered through every stage that appear by destroying certain enemies: Shooting down colored waves of enemy planes spawn items like "S" power-up icons, point bonuses and extra lives. Certain enemies on the ground spawn "B" icons that increases the player's bomb stock when destroyed. Every time the player lands at a runway beyond the first takeoff, the amount of bombs multiply 3000 points to the player's total score. Players are given three lives initially and bonus lives are awarded at 50000 points and thereafter. The game employs a checkpoint system in which a downed single player will start off at the beginning of the checkpoint they managed to reach before dying. Getting hit by enemy fire will result in losing a live, as well as a penalty of decreasing the plane's firepower to his original state and once all lives are lost, the game is over unless players insert more credits into the arcade machine to continue playing. Completing the last stage restarts the game with the second loop increasing in difficulty.

Most of the fundamentals of this game work in a similar way to Desert Strike. You pilot a helicopter or a three-barreled tank through 14 increasingly tough multi-phase missions, each of which is preceded by a full briefing and a shopping phase. Before each phase you can enter the shop and upgrade your weaponry, paying with golden medals gathered during previous phases. Your starting weapons are the chain gun and rockets/tank shells. Every weapon has three upgrade levels. After that, you can decide how much ammunition for each weapon you want to load into your vehicle's weapon bays, switch between the tank and the chopper (which can only be done between phases, and some of them don't give you the choice), choose one of the three special weapons and adjust the fuel/armor/speed characteristics. All these preparations are surprisingly complex for a shooter like this, and a bad configuration can make the game really hard (no fuel in the middle of the desert, or a paper-thin armor are just two examples). Missions are set in the desert and jungle as well as over the sea and in snowy regions. Most often your objectives are, obviously, to seek and destroy, while performing some rescue operations and gathering as much powerups as you can. The powerups consist of ammunition, fuel, medals, and others. A scanner is installed into the vehicle to guide you, as is a mapping system and a limited shield. Unusually, the game only scrolls vertically even though you have full directional movement. When you rotate the direction the ground moves underneath you, ensuring a more realistic effect and smartly mimicking motion effects.

Lock On is a side-scrolling shooter developed and published by Philko in 1991 The game is similar to Carrier Air Wing from Capcom.

As in many other vertical scrolling shooters (including Namco's own Xevious), the player controls a ship, facing the top of the screen, that can move freely while the background scrolls down, bringing enemies in to view; the player may destroy enemies for points. The game uses two buttons - one is used to make the ship fire circular lasers, while the other is used to cycle through its four firing patterns. The red pattern is two lasers in a spiral pattern, while the blue one is one laser straight ahead and one behind, the yellow one is one laser straight ahead, one left, and one right and the green one is two lasers diagonally forward (one to the left and one to the right), and one straight behind; by holding down the button, the ship fires more powerful, spherical lasers. Even though the game is the sequel to Bosconian (which used a synthesized, DAC-generated voice saying "Blast off!" at the beginning of every round), Blast Off had more in common gameplay-wise with Namco's own Dragon Spirit than with Bosconian; this is especially noticeable in the third area of every world, where the player's ship undergoes an increase in size, and must destroy a boss. Despite several gameplay differences, the connection with Bosconian was emphasized in the marketing of the game, with the hexagonal space stations from Bosconian appearing in Namco's press literature, and on the game's title screen, and also making appearances in the game itself - and the game is also worth noting for its usages of various Engrish phrases, such as "To push start only 1 player button" (on title screen), "Go next" (at end of world), "Congraturations" (at end of game) and "Entry your name" (on high score table). There are a total of six worlds in this game, and each one has three areas (so there are a total of eighteen "stages" to play through).

Strike Gunner S.T.G is an Action game, developed by Athena and published by Tecmo, which was released in 1991. A vertically scrolling shooter.

You play a bi-plane pilot on missions to bomb enemy targets. The game has a left-to-right scrolling screen where you shoot at enemy planes and trucks. Fly down and pick up the bomb as you go along.

The NES Port of Sky Kid. You are the legendary Red Baron, flying a plane through a horizontal side-scrolling scenery set during World War I. To complete a mission, you simply need to get to the landing spot on the other side without being shot down, but you can gain extra points by destroying enemy vehicles and planes. For huge points, pick up a bomb hidden in the level (you will be warned by a sound when approaching it) and drop it on a large structure. If you fail to land on the landing strip, you run out of fuel and crash. You can only shoot horizontally and diagonally by tilting the plane's nose. When in trouble, perform an aerial loop with the secondary button, this often destroys other planes and avoids bullets. There is a co-op mode with the character Max as well.

The Super Cassette Vision port of Sky Kid.