@ShikaruAlrighty, Zombehs's concerns are actually pretty much my own concerns.
Our characters come from an Earth that is pretty much the same as ours, perhaps slightly different and what not- but tech wise, everything is roughly the same.
Having a deranged or psychotic character is fine, or a mentally unstable one- just as long as you're able to play them properly and it doesn't cause trouble for the others.
Being a technomancer or someone who creates stuff via technology- Alright, that's also pretty good and works fine as well. Matches the crazy scientist theme, so again, that's fine.
Now, comes to the problem: both the bracer and the gun.
Neither of these will suffice, since the technological advances of the Earth that everyone comes from is similar to our own, and because it honestly doesn't really sit well with me since everyone else has rather sublime and simple equipment starting off. Everyone is basically relying on their powers to survive here, not what they brought with them from the other world, and having someone starting off with superior advanced tech who came from the same world as them would shift the balance of things. Basically, its a power and balancing issue.
Although, if you wanted to spend time during the actual RP and slowly build those items up from scratch using his new found powers, now that's a whole different story and would actually be acceptable, since both the gun and the bracer would start off simple, but gradually get stronger as he makes improvements upon them.
If you're going for a mad scientist in another world idea; then I would heavily suggest removing the bracer and gun, tone down Technomancer so that he can easily make inventions, and
then build upon the bracer/gun/any other ideas you may have.
Our characters are starting off small, and gradually get stronger and more 'heroic' and legendary so to speak.
Everyone should try to keep this in mind as an idea as how their powers will be growing.