Thanks for playing! Well, the Jam is over, so I doubt more people will play it, so the combinations are:
Fire + lightning = Explosion
Fire + ice = water
Fire + wind = smoke
Fire + water = lava
Fire + rock = meteorite
Lightning + ice = nothing, the plan was to add a snowman that could block a hit
Lightning + wind = Thunderstorm
Lightning + water = Nothing, the plan was to add a shock effect that would paralyze the enemy
Lighting + rock = nothing, the plan was to add metal spears
Ice + Wind = Blizzard
Ice + Water = snow
ice + rock = Hail
Wind + Water = whirlwind
Wind + Rock = Sand
Water + Rock = Mud