Metal Soldier Squad 9+

This game is a classic side-scrolling shooter, with a variety of weapons, challenging gameplay, and only 1 player-simultaneous modes. The object of this game is to destroy the Red Falcon, and alien who, along with its minions, has invaded the earth. It's just you against the whole alien army.
The game can be quite a challenge as you die after taking 1 hit, and you only
start the game (normally) with 5 lives. The controls for the game are very
simple:
A - Jump
B - Shoot (Auto fire)
Control Pad - Move left and right, crouch, aim weapon
(Note: To shoot straight down, you must jump up with A, then hold down while pressing B.)
Down + A - Drop down a level (if possible)
Also, I'm not claiming to call everything by its official name, but hopefully
most people won't care.
V. Weapons/Items:
You start out the game with just a basic single-shot rifle. Fortunately, you
can get more powerful weapons (otherwise this game would be extremely
difficult). You can only hold down B to fire multiple shots if you have a
machine gun or laser, and this is probably the best way to fire these. All
bullets strike targets with the same force. The laser strikes with the force of
4 bullets. Upgrades are found by shooting flying capsules, shooting upgrade
boxes, or by shooting brownish-red colored soldiers in the bases.
R - rapid fire - This only affects the standard rifle and the spread gun. Quite
obviously, it just speeds up your bullets.
M - machine gun - Has the advantage of auto fire. Just hold down B for a
constant stream of bullets.
F - fireball - The bullets of this weapon move in a circle about as tall as your
player while they travel forward. I don't particularly like it because the
bullets travel the slowest of any weapon, but you can hit enemies that are
crouched.
L - laser - The laser strikes hard and is equivalent to an extremely fast-firing
standard rifle. Don't hit B rapidly with this one, or your current laser beam
will disappear and a new one will launch.
S - spread - This one's my favorite (especially when combined with rapid fire).
Bullets come out diagonally up and down as well as straight ahead, giving you a very wide range. In a 2-player game where both players are armed with rapid spreads, heads will roll.
B - barrier - The barrier makes you invincible for a little bit. You'll flash
between red and blue. Be very careful with it, though, because it gives you no
warning when it's about to end.
H - health - Added 1 more life
K - kill - Killed all of enemies in the current view