Terrified said:It was an action platformer that took place in a forest of sorts. All I can remember is that the guns you had were customisable, and collecting different bits of gun (may have been powerups) allowed you to shoot extra bullets. I also think there may have been a flamethrower attachment, although again I may be misremembering. Platforming was slightly Metroidy, in terms of reaching new bits of the forest as you progressed.
Well, it screamed Turrican, right up until the forest. That threw me, though. My first thought was Elf, but there's a lot of detail in the game that's not in your description - and the weapon isn't strictly a gun, although it does effectively fire bullets.