Why don't you put a roster?
Like an entry challenge, who pass that is inside the circle. For sure work for ttrr, like on a Nail map wormers who cannot do less than 47 are out, it's easy. But you can set also for WxW like touching 4 walls in 15 secs. NOt super pro time or time that people spend hours to do. Just a normal time that you can do from cold with wasting time. ROper the same: wxw x2.
For bng dunno, something like destroying a worms of 100 hp in 3 minutes (you create the map putting a red cross where the worms has to be put in)
elite dunno, ...