I'm not really that familiar with the Metroid series. The only other one I have ever played so far is Metroid Pinball, so I'm totally not clued-up on the original that appeared on the NES back in 1986. But I did go for this one because I heard that the original Turrican game was based partly on Metroid.
And while the similarities are plentiful this is still a great game in it's own right. Old-fashioned 2D platformers are always brilliant and it's one of my fave genres. Fusion involves lots of running around in a huge, abandoned space-station, visiting my departments and sub-departments, blasting away at alien scum and trying to figure out what happened to everyone. The level designs are awesome, with loads of hidden extras and secret passageways. You'll still be able to memorise your way around though.
The graphics and sound effects are dead cool but the generic music is a bit of a let-down. Some of the bosses are unbelievably hard and you'll end up having to stop yourself from smashing your Nintendo against the wall. Fight the urge, there is always a way, always a pattern to follow to kill them. But it's finding the courage to face it for the 86th time that really matters.
Definitely one of the best games on the GBA, but perhaps a bit too short. I would have liked to have kept going and gaining more and more and MORE power-ups. But hey, it's still worth the money.
Graphics A Sound B Gameplay A- Lasting Appeal B+