+4 can also go in a +2 but now only +4s can be player—you can’t go back to +2.
You can skip a skip, but then it skips two people. If the person who it lands on skips again, it skips three people, and so on. Fun to figure out when you’re all wasted.
I use the rule "face cards can interact with each other".
You can add +2's, you can throw in +4's. All the normal rules apply still, so color matters. Throwing a +12 at someone is almost as amazing as them dropping a reverse to win. The only rules change beyond this is that skip changes from skip the next person to skip you drawing, thus passing it along.