Right now I'm working on a GM's guide for USR, which details how to create your own worlds, creatures, items etc. I wanted to share with you how to make your own enemies, as I know this has come up around the web.
USR is a simple, so you don't have to put a lot into creating a foe if you don't want. Unlike with PCs, you don't have to stick with the d10,d8, and d6 array when assigning dice to attributes. You could have something with Action d8, Wits d8 and Ego d6 if you wanted. For instance, here's a Skeleton Warrior I just cooked up:
Armour: Target Shield (-1)
Easy, right? For low level enemies, I wouldn't give them many specialisms - maybe one. Also, just because I haven't listed a weapon, doesn't mean there can't be an implied one to add flavour to the enemy. For instance, Skeleton Warriors may use rusted scimitars, but since they're low level I'd just imply that's what they had or maybe have the weapon count as +0.
You can easily make an enemy on the fly with USR. Say you're running a western and you need a couple of bandits to harass the PCs, you could say Bandit #1 has Action d6, Wits d8, Ego d10 and Hits 6. He also carries a revolver (+1). It's that easy. Then again, you could flesh him out a bit more:
Specialisms: Ego - Charms the Ladies (+3)
Wits - Knows his way around town (+2)
Weapons: Six-shooter (+1), Ammo (2 rounds), Boot knife (+1)
Equipment: Leather holster, 5 dollars, 10ft rope, spurs.
You could even give your enemies extra effects just to keep the players on their toes, e.g. giving a cobra a poison attack where if the cobra wins a round of combat the player must test Wits or suffer 1 hit of poison per round. You could just write this in the weapon section if you wanted. Here's a foe with a couple of extra abilities on top of the standard ones:
X-154 Hunter Droid
Specialisms: Wits - Find Life-forms (+3), Hack Computer (+3), Analyse Chemicals (+2)
Action - Enhanced Targeting System (+4), Jet Pack (+2)
Weapons: Gatling Gun (+3), Tear Gas (+1) - Target must pass medium Action test or be unable to see for 1 round; Cluster Grenade (+2) - roll 1d6 to see how many grenades hit the target; Plasma Cannon (+5) - May be used twice before it overheats. Cools down in 1d10 rounds.
Armour: Titanium Alloy (-3)
You can be as basic or as complex as you like. USR's combat is built to be modular, so you can throw in whatever you want, whether it's special attacks, status effects or just changing weapon damage output.
You can also assign levels to enemies if you wanted. Your standard 1st level enemy would have 3 specialisms or fewer and no weapon (unless it's an implied weapon). 2nd level would have either an added specialism, an extra +1 to one of their 3 specialisms or a +1 weapon, and you can carry it on from there. You can also add a level for having a die one step above what it should be. For example, the X-154 Hunter Droid has d10, d10, d6, so you would add an extra level since it has one die step higher than usual. You certainly don't need to give your enemies levels as it's pretty easy to work out how players would fare against one of your creations.