You know, I have A LOT ideas for weapons. Though they're not very conservative, but still I think they fit JJ well. Here's an example weapon list.

1. Blasters
a) LFG-2000 (Jazz's basic) - shoots light energy shots, which don't do much damage, but since the energy is drained from the environment into the gun's battery, the ammo is pretty much infinite. If you shoot fast enough you might use up energy faster than it recharges, but in such occasion hide for a moment or switch the weapon to let it recharge. You can also hold down the shoot key to charge a more powerful shot, but it'll take more energy.
b) LFG-3000 (Spaz's basic) - the difference from LFG-2000 is that it shoots faster, but the shots are less accurate. The battery is a bit stronger, so even with this fast shooting energy will run out with the same speed as in LFG-2000.
c) LFG-1500 (Lori's basic) - the difference from LFG-2000 is that it shoots energy bullets in a shape of a disc - they deal more damage, but use up the battery faster.
d) LFG-4000 - shoots three energy bullets at once - has thrice stronger battery than LFG-2000, so battery drains with same speed.
e) LFG-5000 - shoots an energy ball that spreads into 10 typical blaster shots on impact - has only twice stronger battery than LFG-2000, so needs to recharge pretty much.
f) extra battery - can be connected to character's basic blaster, lets you shoot longer before you'll need to stop.
g) accumulator - can be connected to character's basic blaster, increases damage dealt by shots but also uses up batteries faster. Basically more power -> bigger need for batteries, so hunt them down with same effort.
h) interface update - can be connected to character's basic blaster, lets you use 2nd level ammo (powered-up ones from Jazz2) in the blaster.

2. Bouncers
a) using in your basic blaster - you can use basic bouncy bullets (blue), or 2nd level (purple) if you got an update for it. That way you shoot them like in Jazz2, with normal speed (even in LFG-3000).
b) BBT-21 - supports blue and purple bouncy bullets, shoots them with big speed, but the rest is like blaster.
c) BBT-3:1 - supports blue, purple and black bouncy ammo, shoots three bullets at once in different, random angles.
d) BBT-S15X - supports blue and purple bouncy ammo, shoots with great power, so the bullets either fly very far or bounce off walls very aggresively.
e) blue ammo - slightly more damage than blaster shot, lightweight.
f) purple ammo - more damage, heavier than blue, but also more bouncy.
g) black ammo - highly explosive, heavier than purple, but as bouncy as it is.
h) visor - compatible with BBT-S15X, lets you zoom the vision for sniping far positioned enemies.

See as I just killed the Fast Fire pickup. ^^ There will be more to come if you like my ideas. Now, about the HUD appearance - anyone remember the weapon box from JJ1? How it contained the weapon's name and an example of bullet's track? That's the option. I'd also implement a pause feature from Ratchet & Clank, that lets you read weapons' descriptions in the pause menu (there was also same thing for special moves, but I doubt we'd need it).