It gets a shield when stepping on a trap, so plan your movementa carefully
When in supercharged mode it moves more quickly, so you need a way to get some distance. Swiftthistle seed, Chains, Potion of Haste, Hourglass, etc. DM-300 moves more slowly through large passages, so use the center of the level to your advantage.
When in supercharged mode, the sparks might give you a hint about which way to go… Don’t step on them though
When D-300 makes rocks fall, look carefully - there will always be a safe spot to move
If you mean DM-300 (boss), here are some tips: