Konami's 1985 hit Gradius is one of the most influential scrolling shooters of all time, so it was pretty tough to follow up. Rather than make Gradius II right away, the company decided to create a spin-off; Life Force — originally known in Japan as Salamander — hit arcades in 1986 and the NES two years later.
Space shooters were some of the first video games ever made, and the genre thrives on iteration; rather than reinvent the "spaceship shoots aliens" wheel, most developers are building on what came before and refining the concept. Despite being labelled a spin-off, Life Force introduced many elements that would be incorporated into all future entries of the Gradius series, running under the radar as one of the most influential shooters of the late 1980s.
As we've written about recently, arcade-to-NES ports were a notoriously tricky affair, with games often changed entirely to work with the limited horsepower of Nintendo's first home console. Life Force isn't quite as pretty as its arcade counterpart, but still translates to a fluid, fun NES experience; most importantly, it retains the arcade original's two-player cooperative mode.
Life Force's two-player mode is the biggest leap forward over the NES version of its predecessor Gradius – blowing up aliens together with a friend is much more engaging than the comparatively drab experience of doing it alone. In a change of pace, the game switches between vertically-scrolling levels and horizontally-scrolling levels to keep the gameplay interesting. The innovative power-up system from Gradius makes a return; rather than pick up items and instantly switch to a new weapon, Life Force lets you build up saved power-ups to cash them in whenever you want. The more items you have saved up, the more powerful weapons you can unlock, and once you've cashed in one power-up, you can still collect more items and stack power-ups on top of each other for some deadly combinations. It's an intriguing risk vs. reward system; you're inclined to save your items so you can gain the more powerful weapons, but if your weaker weapons cause you to lose a life in the meantime, you lose all the items you saved up.
Power-up mechanic aside, Life Force is a fairly standard side-scrolling shooter with some unique level design choices. Controls are tight and simple, with B to fire all weapons and A to redeem your power-ups. There are tough enemies to fight, but often the most dangerous part of each level is the environment itself, which can move and modify itself to pose a serious threat to your ship's safety with unforgiving hit detection. The outer-space locales range from the surface of a star to a colossal Egyptian astro-pyramid to leaping Easter Island statues (is this Super Mario Land?!). Perhaps the most memorable is one taking place entirely inside someone's giant body, where you work your way up battling evil blood cells and ribcage lasers to reach an enormous space-skull whose eyeballs detach from their sockets and chase you around the screen.
Life Force doesn't have the audiovisual flair of the arcade original, but it still looks great for an NES title and doesn't feature much slowdown until later levels when you start to get a dozen or more enemies on-screen at once; the music and sound design are above average, despite a few glitches where sound effects won't kick in right away at the beginning of each level. The difficulty is typical for a side-scrolling arcade shooter, ranging from fairly easy in the first two levels to infuriatingly difficult later on. Luckily for those of us without total mastery of the genre, Life Force supports the legendary Konami Code, but if you're a purist you'll have a challenging time completing the game with only three lives. Some of the environmental hazards can be incredibly unfair, like solar flares on the star surface level or arteries on the body level, where level elements will pop up out of nowhere to destroy your ship without giving you a chance to react.
If you're itching for some cooperative old-school space shooter action, Life Force will scratch your itch like a kind old friend you've known for years. It's a fairly standard side-scrolling shooter with enough twists on the formula – alternating vertical/horizontal levels, a unique stacking item system and some trippy level designs – to make it stand out in the crowd, a natural step up for veterans of the original Gradius. Life Force doesn't have the immediate name recognition of some of its peers, but it's well worth the time for any fan of the genre.