TL;DR

Rulings

For many playtest cards, you’ll need to make a generous assumption that basic game rules would be updated to allow them to work. The Mystery Booster 2 Playtest Card Notes section (reproduced here in individual Gatherer rulings) provides guidance for fitting these cards into the existing rules structure. — Playtest cards aren’t legal for play in any tournament format other than Mystery Booster Limited formats. On the other hand, we expect they will spice up a wide variety of non-tournament games (as long as everyone’s on the same page about using them!). — Playtest cards use a modified version of game symbols, such as {T} and {W}. These modified symbols should be treated as the standard symbols during play. — Yes, a keyword action is technically also a keyword, but it’s not possible for a creature to have a keyword action without having some other ability. — You can target a creature with no abilities other than keywords with TL;DR, but when TL;DR resolves, it won’t exile that creature.