If anyone still cares, I got the play/wiggle out of the chainring by tightening something in the BB, but now my damned crank arms are moving. Like, I can move the left crankarm and the right one will move along with it. They're moving around an inch or two, just back and forth, this is what I must've been the play I was feeling when I was slowing down. Oddly, the chainring isn't moving at all, so I'm assuming it's directly connected to the BB, while the crankarms are all by themselves having a party, wiggling around and making me feel uneasy.
My rear wheel's still trash, so I still need to get a new one of those, which really has me kinda of pissed off since I haven't ridden my bike in a while due to that.