Any% means literally any percent completion of a game. Beating BL2 should count as beating the game since it's the last bomb. So starting on a fresh save should allow you to skip certain bombs cause the next section unlocks after beating 2-3 bombs on a previous section - t-e beating the first 3 bombs in section 3 would allow you to start section 4. That's how i think the "Any%" category should be. As for "All bombs (detonation allowed) is good as it is. Any% at the moment is "100% completion" since you're supposed to successfully defuse every single bomb and get the "Defused" mark. That's a 100% game completion imb.