Yes, but it has almost-nothing to do with the bonus feats.
The bonus feats that the artificer gets are mostly fixed, and mostly don’t really combine—they just allow you to make a variety of items. They don’t really build on one another, as few items require more than one of them, so you are always using one at a time. That many bonus feats is certainly good, but it’s not really game-breaking in and of itself. Compare to the fighter, who gets similar number of feats and they can be chosen from a rather-large list, and they are typically chosen for synergy. If feats were the biggest concern here, the artificer would look paltry compared to the fighter.
But feats aren’t the biggest concern.
This feature is preposterous. First, there is no mention in the text of a limit on how many inventions can be made, or a limit on how many spell effects can be shoved into them. Table: Artificer certainly suggests some kind of limit, but it’s unclear how it applies. That’s a pretty massive thing to miss.
I will take the most conservative approach and assume the limitation is on the total number of spell levels, across all devices.
But then we have a couple of gems
An artificer has access to both arcane and divine spell lists, but only up to 4th level.
Don’t let “both” fool you: there is no limit or list given anywhere in the class. To all appearances, the artificer can use any spell list ever, anywhere. I guess occult spells are off-limits (though no doubt solely because this was published before Occult Adventures)—there’s probably a few gems in there that you’d be sad to miss, but really, it’s hard to sympathize. This is ridiculous, and also encourages spell list poaching. What’s that, you want major creation but you’re limited to 4th-level spells? Oh, look at that—the summoner gets it as a 4th-level spell. Guess the artificer is totally ready to rock that.
Any number of spells can be combined into a single device.
Oh, like a staff? OK, I guess, that’s not really a big deal...
Combining multiple magical effects into a single device means that both effects function simultaneously upon activation (effectively casting two or more spells at once)
What?! Are they absolutely out of their minds? Actions are the most valuable resource in the entire game, and the artificer is giving them out like candy.
Weird science devices are temporary and unreliable. They are able to be used reliably a number of times per day equal to 1 plus half the class level of the artificer who built the device (rounding up, naturally).
That’s... that’s rather a lot. Way more than spells, you realize that, right? That isn’t a limitation, that’s a huge benefit.
The device may be used by anyone — but if used by someone other than the artificer who built it, it requires a Use Magic Device roll at DC 15 to activate (a failed roll indicates that the device fails to activate for that user, and a roll of 1 means that the device breaks down for good).
Oh good, why should the artificer be alone in blowing the action economy out of the water?
And then we have an example, which largely confirms that, yes, the artificer is that crazy. We have a 5th-level artificer, Roderick, combining lightning bolt (3rd-level spell), inflict
light moderate wounds (2nd-level spell; note the description refers to inflict light wounds as a 2nd-level cleric spell, and it is not), and shield (1st-level spell). Under the conservative interpretation about the limits on the number of weird science inventions, above, that leaves Roderick only two 1st-level effects, which he can either combine into a single other invention, or leave separate as two inventions—poor Roderick (insert eye roll here).
Anyway, the example continues: as a standard action, Roderick can activate his gun, simultaneously shooting a lightning bolt, inflicting a light wound, and shielding himself. It took him 24 hours to complete (presumably over three days, with the usual 8-hour workday limit in place, though the feature really should say), and he can do that 5 times per day—before he has to start making Use Magic Device checks. Those checks are fairly hard—DC 28 for his sixth use of the day, DC 31 for the seventh, and so on, but at that point he has blown an enormous amount of spell power compared to literally any other class in the game. A 5th-level wizard has one or two 3rd-level spell slots, from which he might cast only lightning bolt. A 5th-level sorcerer doesn’t even have 3rd-level spells yet. And while those checks are hard, they are not impossible. So Roderick can totally work towards being able to get 6, 7, maybe more uses out of this thing.
But worrying about longevity is kind of burying the lede. In most campaigns that kind of thing only sort of matters. On the other hand, the action-economy advantage of weird science is absolutely unparalleled. There is no way in the entire game to cast lightning bolt, inflict moderate wounds, and shield all in one turn. Not at 5th level, not at any level. Quicken Spell could get you one extra spell in a turn, but not two. Maybe you could count time stop (!) as allowing it—kind of. And even getting two spells costs you mightily with Quicken Spell: that extra 4 spell levels mean you have to burn a 3rd-level slot for lightning bolt and a 5th-level slot for shield (or a 6th-level slot for inflict moderate wounds)—that’s impossible before 9th (or 11th) level, and even then you get to do it once or twice. Not 5+ times per day.
This feature is lifted straight from the Eberron Campaign Setting artificer. This feature is the reason that the Eberron Campaign Setting artificer has a very strong claim to being the most powerful class in all of D&D 3.5e. And it returns, on top of weird science.
For the Eberron Campaign Setting artificer, the item creation ability breaks the game and is basically the reason the artificer is so good (though, to be fair, the infusions are also extremely powerful). For this artificer, item creation is an also ran. It pales in comparison to weird science.
The Eberron Campaign Setting artificer had a similar feature, gained at the same level, because this class is pretty close to a direct port of that class, weird science aside. That feature allowed you to retrieve the XP put into an item—one twenty-fifth of its value. Pathfinder removed XP costs for creating magic items, so this had to change. And boy did it change—now it returns 100% of the money put into it. Sure, that’s the crafting cost—half its base value—but the sheer efficiency here is worth pausing. It basically means that the artificer can always sell any item, anywhere in the world. Which could be justifiable as a quality of life thing, but on top of everything else the artificer gets, it seems like that quality is very fine indeed.
More importantly, there is no restriction on what sorts of items the artificer can destroy this way, beyond needing to have the relevant item creation feat. Artifacts are probably safe, if we intuit some “item creation feat” that the artificer does not (and cannot) have in order to create them, but that’s still a scary possibility. Artificers rapidly destroying plot-relevant items could derail a campaign pretty hard.
Oh good! Couldn’t let this artificer miss out on the last of the Eberron Campaign Setting goodies. Metamagic is very powerful, particularly when you don’t have to pay for it in spell slots—because even though this costs a whole bunch of charges from your wand, those charges are purely linear. Quickening, say, shield costs 5 charges off of your 1st-level wand—approximately 75 gp. A single charge off of a wand of quickened shield costs 675 gp. But more importantly, you can do this above and beyond the usual limits on spells or wands. You can quicken 4th-level spells, even though that should result in an 8th-level spells, even though you are only 6th level and shouldn’t have 4th-level spells in the first place, to say nothing of 8th-level spells. You can do this even though wands can’t hold 8th-level spells at all.
This feature is fantastically powerful. It was for the Eberron Campaign Setting artificer, it is here as well.
Improved Metamagic Science
Less useful, ironically, than metamagic science, but just a reminder that this is here.
I’ll be honest—this artificer never made it to my game. I was thinking of playing one—the Eberron Campaign Setting artificer is ridiculously overpowered, so I was interested in an alternative—but this option was discarded almost immediately. I have played an Eberron Campaign Setting artificer—which this class is an almost-direct port of—and I have also seen that artificer played to the hilt. And it can be absolutely ridiculous. It is overpowered, really treading the line of being totally game-breaking.
This artificer gets almost everything the Eberron Campaign Setting artificer got. Certainly more than enough of what that artificer had to make this overpowered for the same reasons. But then instead of infusions, which were quite good, this artificer gets weird science. And weird science is absurd. It’s so good that every thing else this artificer gets—everything that made the Eberron Campaign Setting artificer broken, or nearly so—becomes an entirely secondary consideration. The incredible action economy, paired with substantial longevity, of weird science makes it easily the most powerful class feature I have ever seen in print for either system. And I have read Frank & K’s Tomes, which were literally an attempt to print intentionally-overpowered classes for high-powered games by people who knew quite a lot about 3.5 optimization...
If allowed, this artificer would be the strongest character in the entire game by a massive margin. Please, do not add this class to your game. I can’t believe I’m doing this, but I will seriously recommend the Eberron Campaign Setting artificer—ported to Pathfinder, it’s not terribly hard—over this. And I never recommend the Eberron Campaign Setting artificer. But it’s still better designed, better balanced than this. It’s much better designed and balanced than this.