How about some weapons taken directly from Cave Story Doukutsu Monogatari
Enemies will drop small to large gems used to upgrade (or downgrade) weapons...
Polar Star
level 1: A small beam that travels a small distance, then explodes causes minimal damage, but has no ammo and is rapid...
level 2: 2 beams next to each other... longer range... a little stronger... bigger boom, no ammo is used...
level 3: A big beam that travels a long range... reload rate is slowish... damage is good... no ammo used
Fireball
level 1 - a weak fireball that travels along the ground... useful on slopes, if enemies have high ground
level 2 - travels a greater distance, is stronger, bounces...
level 3 - Travels until a wall gets in the way... more powerful... leaves a trail of fire
Missle launcher
level 1 - ammo max = 10 can cause great damage as a direct hit... low splash damage, slow. best used on groups
level 2 - ammo max = 30 causes great damage to anything that it hits... much larger splash radius, rocket is twice as large
level 3 - ammo max = 70 basically it is 3 of the level 1 rockets per shot... each with a level 2 power and explosion
Bubbler
level 1 - ammo max = 100 ammo regenerates at 2 per second... very weak but easy to level up... incredibly short range
level 2 - ammo max = 200 ammo regenerates at 10 per second... hold the button down for rapid shots... medium range... not exactly a sniper weapon... effective underwater
level 3 - ammo max = 500 ammo regenerates at 5 per second... hold the button to create bubbles that will circle you... if more then 15 are active, they will shoot forward as ice balls... weak, but rapid
Blade
level 1 - only 1 shot at a time! does a ton of damage... but range is quite limitted.... hard to level up...
level 2 - only 1 shot at a time! does more damage, and penetrates through enemies to ones behind them... however, range is even shorter...
level 3 - only one shot at a time! weakened damage individual hit wise, shoots a spirit forward, and when it hits something in range, it will explode into a fury of deadly sword slashes... downgrades in one hit, regardless of weather you want to or not
Nemesis
level 1 - any gems will "upgrade" it to a weaker form! so watch it! Shoots an extremely powerful lightning bolt... incredible damage
level 2 - shoots a small bolt of energy (link gun) that does little damage...
level 3 - "shoots" a bubble (level 1 bubbler) with half range and no damage! get hit with anything to "downgrade" it...
Machine gun
level 1 - max ammo = 100 ammo regenerates at 3 per second... rapid, but weak... shoots small, visible, bullets... causes ok damage
level 2 - max ammo = 50 ammo regenerates at 10 per second... shoots rapid tiny lasers... visible... not exactly the longest range... stronger
level 3 - max ammo = 200 ammo regenerates at 5 per second... shoots big energy blasts rapidly. WARNING--May cause user and victim to fly around!
Snake
level 1 - short range, good damage, goes through walls...
level 2 - longer range, leaves a thin trail of energy that does low damage, the ball itself has a long range
level 3 - awesome range (not infinite), makes a fire trail that settles to the ground gradually, slow, inaccurate
Spur
The most powerful weapon... charge for powerful effects!
level 1 - a polar star blast at level 3... same damage... infinite range
level 2 - a simple beam that hits for weak damage anything that touches it
level 3 - a double beam that can penetrate enemies, hitting multiple targets
MAX - A powerful, deadly, long charge time beam that can and will annihilate anything that touches it!!!
