It's a harmless time-waster at best, and a pain in the clicker at its worst.
A quick rundown of all the weapons:
- The 'single shot' is the embodiment of carpal tunnel syndrome... damage isn't awful, but the fire rate is absolutely abysmal. If you hold down LMB with this and most other weapons, you get maybe two shots a second; if you click rapidly (or use any sort of auto-clicker), you can get almost ten shots out per second, though you only need five for the most basic enemies.
- The "flamethrower" is useless. Its high fire rate is made worthless by the rate it chews through ammo and the pitiful damage it deals. You might as well shoot feathers.
- The "laser" is the first good weapon of the game: incredible damage and what looks to be a branching second shot after the first connects. It'll take out most weaklings in fewer than three shots, and the piercing aspect is great on bosses.
- The "C4" is a guaranteed OHKO against most weaker enemies... the problem being that it's a mortar shot. Once fired, it IMMEDIATELY sinks toward the ground and explodes on a time delay. In other words, useless against the plethora of jumping enemies and flying bosses you've already encountered before receiving this weapon.
- The "sawblade" is basically just a wider single shot projectile, but slower. The Metal Blade from Mega Man 2, this is most certainly not. And while the added size of the shot might help your accuracy, the damage required to kill one enemy with it is not worth it.
- Finally, the "orbit" is, understandably, the best weapon in the game: all the fire rate of the flamethrower with the damage of a laser shot. It doesn't chew through ammo quite as fast since you can more easily control your number of shots, but it felt very unfulfilling to get this last and not be able to play around with it more.
As far as gameplay goes... everything is as you'd expect. Controls are decently tight, aiming is a little tricky with such a tiny reticle (but you get used to it after a while), and I wouldn't call any of the bosses hard, per se. But after ten years, I wouldn't say this game has aged very well at all.